Bird Cams FAQ: Barn Owl Nest

September 1, 2010
Barn Owls on the bird cam Barn Owls on the Texas Barn Owl Bird Cam.
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Answers to your questions about the Barn Owl nest. If you’re looking for the answer to a specific question, type control-F (command-F on a Mac) and start typing in your search terms to quickly find the answer.

About This Nest

Where is the nest located?
How long have the owls nested in this location? Will they use the same nest site again?
Do you know how long these owls have been mates?
How can you tell which one is female and which one is male?
How old are the adults?
Do they have names?

Natural History

How big are Barn Owls?
Do they mate for life?
How do they choose a mate?
How old are they when they have their first nest/nestlings?
Do both parents sit on the nest?
Doesn’t the female get hungry while she sits on the nest all day and night?
How big is their territory? And how far do they travel to find food?
What do they eat?
How much do they need to eat?
Do they eat the bones too? Why do they eat the bones?
That bird just threw up. Is it sick?
What’s the white film that you sometimes see over the bird’s eye?
Do owls have teeth?
Why is the poop white?
How do they get water?
Do they sleep?
Do they only hunt at night?
Do they have a sense of smell?
How well can they see?
How well can they hear?
What kinds of sounds do they make?

Nests and Eggs

Do Barn Owls build a nest?
How many eggs do Barn Owls lay?
When are the eggs laid?
How long does it take for the eggs to hatch?
How big are the eggs?
No one is sitting on the eggs or young. Won’t they get cold?
What happens if the eggs are damaged?
What is “pipping”?
When the chick is still in the egg, how does it get air to breathe?

Chicks

Which parent sits on the nest with the young?
Why hasn’t one of the eggs hatched even though the others have hatched?
Which parent feeds the young?
When did the chicks hatch?
Are the chicks males or females?
How can you the individuals apart?
Do the chicks have names?
Are you going to band the chicks?
How big are the chicks?
The chick seems hungry. Why haven’t the parents fed it?
Won’t the babies get smothered from the parents sitting on them?
Why is that big one picking on that little one?
Will all the young make it?

Why won’t the Cornell Lab intervene at the nest to save the owlets?
Will the Cornell Lab intervene if the nest is abandoned?
Questions and Answers About Texas Barn Owl Events, June 6-7, 2016?

When will the chicks leave the nest?
When does the chick get adult plumage?
Do the parents feed the young birds after they leave the nest?
How do the nestlings get water?
Why are the Barn Owls panting? Are they too hot?

More facts

Where do Barn Owls live?
How many Barn Owls are there?
How long do they live?
How many young do they have in their lifetime?
The Barn Owls in my area look different than the ones on camera. Why?
What predators are threats to Barn Owls?
What other dangers do Barn Owls face?
Do Barn Owls migrate?
Do the young stay in the same area as the parents after they are independent?
Are Barn Owls aggressive? How do they attack?
Where can I see a Barn Owl?
What can I do to help Barn Owls?

Camera

Does the camera bother the birds?
How long will the camera stay on?
What type of camera is being used?
Why is the nest so bright at night?
Does the light disturb the birds?

Nest and Eggs

Where is the nest located?

The Barn Owl nest box is nestled in the rafters of a large open-air pavilion on a ranch in Texas. The building is surrounded by grasslands and scrubby forest.

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How long have the owls nested in this location? Will they use the same nest site again?

The box has been occupied on-and-off by Barn Owls for many years, but we do not know if the same individuals used this box previously. Research is unclear whether Barn Owls reuse a nest site or whether nest sites are reused yearly, but by different pairs. The Cornell Lab previously featured this nest site online in 2005–11, during which time resident owls attempted to nest 11 times. Seven of these attempts succeeded in fledging at least one young. The camera system was updated in 2013 and a pair of owls arrived at the box during the last week of February 2014. We hope that Barn Owls will continue to use this nest box, but we don’t know if the same adults will return every year.

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Do you know how long these owls have been mates?

Little is known about the two Barn Owls that have taken up residence in the Texas owl box featured on the Bird Cams. In 2013, 2014 and 2015 a pair successfully fledged young owls from this site. Barn Owls may nest at the same site year after year, but it is unknown if the same pair nested in this box in previous years.

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How can you tell which one is female and which one is male?

In many owl species it is difficult to tell the male and female apart, but with Barn Owls, color and size can almost always be used to accurately distinguish the sexes. Though variation in plumage may overlap between males and females, in general (and at this nest), the female is larger than the male and has a heavily spotted chest with more color on her head and body. In contrast, the male appears very white and pale.

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How old are the adults?

We don’t know. Barn Owls may start breeding at one year of age and there are reports of individuals living into their twenties in the wild.

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Do they have names

In the Barn Owl Cam community, the male is often referred to as “Dash” and the female as “Dottie”.

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Natural History

How big are Barn Owls?

Barn Owls weigh from just under a pound to about 1.5 pounds. They are 12–16 inches long and have a wingspan of 39–50 inches. Females are larger than males.

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Do they mate for life?

Barn Owls are usually monogamous and stay together for life. If one of the pair dies, the other will find a new mate. There have been reports of polygamy, with pairs raising second broods during a given year with a different mate. There is even one report of polygyny, with two females and one male nesting and raising young together in one nest box.

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How do they choose a mate?

Many details about mate selection are not known. However, males appear to look for females with more spots. Somehow, a higher number of spots is correlated with offspring parasite resistance, and so males that pair with heavily spotted females gain substantial reproductive benefits.

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How old are they when they have their first nest/nestlings?

Barn Owls usually start breeding at about a year old.

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Do both parents sit on the nest?

No, just the female. She has a featherless area on her abdomen called a “brood patch” which is designed to keep the eggs warm. This patch has lots of blood vessels just beneath the skin that transfer heat to the eggs. Incubation begins after the first egg is laid and the female only rarely leaves the nest during this time, and only for brief periods.

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Doesn’t the female get hungry while she sits on the nest all day and night?

The male delivers prey to the female during the time she is incubating the eggs and brooding the young chicks. In many cases the male will bring excess prey that is stored in the nest for later consumption.

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How big is their territory? And how far do they travel to find food?

Home ranges of the Barn Owl are highly variable and vary in relation to prey density and habitat characteristics. In the U.S., home ranges of radio-tagged individuals are about 740–1800 acres, roughly 1–2.5 square miles. Hunting areas may be located outside of this home range, but usually only by a few miles. When lots of nest sites are available and prey populations are abundant, many pairs may nest in close proximity and share a hunting area.

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What do they eat?

Barn Owls eat mostly small mammals, particularly rats, mice, voles, lemmings, and other rodents; also shrews, bats, and rabbits. Most of the prey they eat are active at night, so squirrels and chipmunks are relatively safe from Barn Owls. They occasionally eat birds such as starlings, blackbirds, and meadowlarks. Amphibians, reptiles, fish, insects, scorpions, and crayfish are rarely taken. Nesting Barn Owls sometimes store dozens of prey items at the nest site while they are incubating to feed the young once they hatch. It has not been determined whether Barn Owls are specialist or opportunistic predators. Though the owls appear to be specialized in hunting small mammals, this actually may only reflect the fact that these prey items are what the owls are most likely to encounter in their nocturnal habitat.

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How much do they need to eat?

The amount of food required for a Barn Owl depends on the size of the owl and the time of the year. They consume more food in the winter and when they are very active. One captive female consumed about 60.5 grams of food per day, amounting to more than 10 percent of her body mass daily.

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Do they only hunt at night?

Barn Owls hunt primarily at night, beginning about one hour after sunset and ending about one hour before sunrise. They occasionally hunt during the day.

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Do they eat the bones too? Why do they eat the bones?

Owls typically swallow small prey whole, bones and all. Bones are broken down in the stomach to provide important nutrients such as calcium and phosphorus. Any indigestible parts of prey such as fur and undigested bones are regurgitated as a pellet. Barn Owls usually cough up pellets once or twice a day.

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That bird just threw up. Is it sick?

You probably observed it regurgitating or “casting” a pellet. When a prey item is swallowed whole, indigestible parts of prey, such as fur, bone, and tough insect parts, will form a pellet in a muscular area of the stomach called the gizzard. In North America, Barn Owls have been found to produce one to two pellets per day on average. The minimum interval between eating and casting is about 6.5 hours, but repeated small meals at intervals of less than 6.5 hours inhibit pellet regurgitation and result in large pellets containing remains of many meals. Pellet regurgitation appears to be stimulated by the sight of a potential meal.

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What’s the white film that you sometimes see over the bird’s eye?

Birds have what is known as a nictitating membrane or “third eyelid.” This is a clear eyelid, closest to the eyeball. It is transparent and can close and protect the eye when hunting.

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Do owls have teeth?

Like all birds, owls do not have teeth. Owls swallow food whole or rip it apart in their beak and swallow pieces.

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Why is the poop white?

Bird poop is actually brown. The white pasty excrement is uric acid, the equivalent to a mammal’s urine. Mammals excrete waste as urea dissolved in urine; birds excrete it as uric acid, which has a low solubility in water, and so it comes out as a white paste.

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How do they get water?

Barn Owls get most of the water that they need from eating their prey. They have almost never been observed drinking water in the wild.

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Do they sleep?

Yes. When asleep they will close their eyes.

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Do they have a sense of smell?

Traditionally, scientists assumed that most birds have a poor sense of smell because the area of a bird’s brain involved in smell is relatively small compared with the area found in mammals. However, recent research reveals that some species of birds have a high number of active genes that are associated with smell. Scientists have also discovered that some species of birds can tell each other apart by smell. So, though we don’t have all the details, and no specific studies have been conducted on Barn Owls, they probably do have some ability to smell.

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How well can they see?

Barn Owls have excellent vision. Owls’ large forward facing eyes give them the best stereoscopic vision of all birds, which is vital for judging distances. The shape of their eyes, their unusually high number of light-sensitive cells, their large pupils, and a reflective layer behind the retina (called the “tapetum lucidum”) give them excellent nocturnal vision useful when hunting at night or navigating dark forests. Like other owls, the shape of their eyes limits their ability to move them in the eye sockets, but their necks can turn up to 270 degrees. This is accomplished by the 14 vertebrae in their necks, twice as many as in mammals. Barn Owls’ low-light vision also appears to be highly movement-sensitive, enhancing their ability to hunt at night.

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How well can they hear?

Barn Owls have superb hearing. Their ability to locate prey by sound alone is the most accurate of any animal that has ever been tested. These owls can catch mice in complete darkness in the lab, or prey hidden by vegetation or snow out in the real world. Like other owls, their ears are placed unevenly on their head and point in slightly different directions, giving the ability to hear where a sound is coming from without moving their heads. Owls can also funnel sound toward their ears by manipulating different types of feathers around the ears and face.

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What kinds of sounds do they make?

Barn Owls don’t hoot the way most owls do; instead, they make a long, harsh scream that lasts about 2 seconds. It’s made mostly by the male, who often calls repeatedly from the air. Females give the call infrequently. These owls also use a variety of other sounds, with a larger repertoire during the breeding season. Distress and warning calls usually consist of a series of drawn-out harsh screams, and both adult and nestling birds will repeatedly hiss to intimidate predators. Males use a soft “purring” call to invite a female to inspect a nest site, and females use this call to beg for food from the male. Twitters and chirrups are uttered by adults and chicks when delivering food, feeding, begging for food, in discomfort, or greeting each other. “Snores” are given mostly by nestlings and females and may be used persistently especially when hungry or upon the arrival of adult with food. When agitated, Barn Owls snap their bill mandibles together. As part of a display flight, males sometimes clap their wings together once or twice. Mobbing calls are an explosive yell directed usually at a mammalian predator. Various other sounds are associated with the breeding season and can be heard during copulation, food deliveries, and greeting. Young begin to use adult calls while still in the nest.

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Nests and Eggs

Do Barn Owls build a nest?

Barn Owls usually use existing cavities and nest boxes, though they have been observed to dig burrows with feet in soft soils of river/arroyo banks in Colorado and New Mexico. They do not usually bring in nesting material, though most females contain the eggs by arranging a cup of their own shredded pellets.

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How many eggs do Barn Owls lay?

Barn Owls lay 2–18 eggs, usually 5–7. There is little correlation between clutch size and latitude. They have 1–2 clutches per year in most areas, but in some climates or in captivity, Barn Owls can breed year-round. In years with abundant food, subsequent clutches may overlap, with the female incubating a second set of eggs and the male continuing to feed the fledged young.

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When are the eggs laid?

Barn Owls may lay eggs throughout the year depending on location. The severity of weather during the preceding winter has a significant effect on the date of first clutches; longer winters with a high number of days with deep snow cover will cause clutches to come later in the year. Another way to predict when eggs will be laid is that egg laying usually happens about one month after courtship begins. In Texas, Barn Owls may lay their first clutch as early as November. The eggs in this nest were laid March 23, 25, and 27. Eggs are usually laid every 2–3 days until the clutch is complete.

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How long does it take for the eggs to hatch?

Usually 29–34 days.

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How big are the eggs?

The eggs are about 1.5–1.7 inches long and 1.2–1.3 inches wide. They are dull white, though are often dirtied in the nest, appearing darker. Scientists have found that Barn Owl eggs are about 30 percent smaller, in proportion to the female’s body weight, than those of other owls. This may allow them to lay more eggs using the same amount of body reserves.

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No one is sitting on the eggs or young. Won’t they get cold?

It is normal for parents to leave the eggs and nestlings exposed now and then. In most cases, they don’t stay away long enough for the eggs or young to suffer harm. Barn Owls have evolved over millions of years to cope with variables such as harsh weather. When the oldest chick is about 25 days old, the female will usually spend less time with the nestlings and increase her hunting efforts.

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What happens if the eggs are damaged?

Although we haven’t observed this scenario in Barn Owls, it is likely that they would respond in a similar way to that of other bird species. In these cases, if only one egg is damaged, the parents generally continue to incubate the other ones. If something happens to the entire first clutch of eggs, most birds will often lay a second clutch if it is still early in the breeding season.

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What is “pipping”?

“Pipping” refers to the process of the chick initially breaking through the shell, using a hard projection on its bill called the egg tooth. The resulting hole is the “pip” that the chick then enlarges to finish hatching.

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When the chick is still in the egg, how does it get air to breathe?

Oxygen gets into the egg through pores in the shell. Owl chicks may take more than 12 hours to make their way out of the egg after pipping. They get their first big gulp of air when they pierce the membrane of the egg under the shell. Once they pip, they keep their bill close to the pip and the growing crack they’re working on.

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Chicks

Which parent sits on the nest with the young?

Only the female Barn Owl incubates the eggs and broods the young. She has a specialized “brood patch” of bare skin that helps warm the eggs and young.

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Why hasn’t one of the eggs hatched even though the others have hatched?

Barn Owls typically lay an egg once every 2–3 days until their clutch is complete. The eggs laid first have a head start and hatch sooner than the ones laid last. In some cases, however, an egg may not hatch because it wasn’t fertilized or because the embryo didn’t develop properly. Eggs do not successfully hatch in many Barn Owl nests. For example, Marti (1994) conducted a 16-year study in Utah and found that only 63 percent of eggs hatched.

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Which parent feeds the young?

The male delivers prey to the female on and off the nest and she feeds it to the chicks by tearing it into small pieces. Often before two weeks of age, the young are able to consume whole prey on their own. At this time, the male will still deliver prey and the female may also begin to start hunting.

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When did the chicks hatch?

In 2014, the chicks hatched on May 10, 11, 14, 16, and 19.

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Are the chicks males or females?

Without DNA testing, it’s almost impossible to tell when they are young. As they get older and achieve their adult size and color, we may be able to guess the sex; females are usually larger than males and have a heavily spotted chest with more color on the head and body.

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How can you tell the individuals apart?

When they are young, the oldest is usually the biggest, and the youngest, the smallest.

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Do the chicks have names?

No.

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Are you going to band the chicks?

Banding birds with an individually numbered ring on their leg is a common practice in ornithology to mark and study individual birds. Special permits are required to band birds for scientific study. If the owls were needed in a study, then we would consider banding them, but presently the birds are not part of a study and we do not plan to band them. In order to avoid unnecessary disturbance at the nest, banding nestlings is done only when scientifically warranted.

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How big are the chicks?

Hatchling Barn Owls may weigh 12–21 grams depending on the subspecies. Barn Owls in the U.S. are generally larger, suggesting that their chicks would be on the heavier side of this range. Growth is rapid, especially during the first month, and the chicks are usually heavier than the adults at the time they fledge, at about 50–55 days after hatching.

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The chick seems hungry. Why haven’t the parents fed it?

As the young grow, they can eat and digest bigger meals and the parents may stay away from the nest for longer periods of time. In cases of severe food shortages, the smallest perish and are sometimes even consumed by their siblings. Though nest failures such as this are difficult to watch, this strategy enables the parents to produce as many young as conditions allow.

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Won’t the babies get smothered from the parents sitting on them?

The parents don’t sit down on the chicks hard enough to smother them. The chicks can breathe even when their parents are brooding them.

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Why is that big one picking on that little one?

This is a natural, well-documented behavior for nestlings of some bird species, including Barn Owls. In general, there is little strife between Barn Owl nestlings other than some squabbling over food. Unlike other species, older Barn Owls chicks may even feed their younger siblings. However, in some cases siblicide and even cannibalism may occur. This is more likely to happen in nests where there is a lack of food.

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Will all the young make it?

Sadly, it is rare for all Barn Owl hatchlings to survive to fledging. One 16-year study in Utah found that, on average, only 63 percent of eggs laid hatched and 87 percent of hatchlings survived to fledging. Similar observations have been made on Barn Owl nests in other parts of the world.

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Why won’t the Cornell Lab intervene at the nest to save the owlets?

Here at the Cornell Lab of Ornithology, we have been closely monitoring and actively discussing the developments in the Barn Owl nest box of Italy, Texas, where today (May 30, 2016) just one of the original six chicks survives. Others have been consumed by their nest mates after perishing, or have been injured and killed by what we assume to be an intruding adult Barn Owl. These circumstances were brought on by a several day period of intensely bad weather, including record rainfall, which limited or curtailed altogether the opportunities for hunting and provisioning the nest.

Such events are difficult to watch, and understandably we have been besieged with requests to intervene and offers to help, either by providing supplemental food or by rescuing the individuals and caring for them in captivity. As lovers of birds and nature, all of us share the feelings of sorrow and empathy for these individuals as they endure mortal hardships in the nest. Like everyone, we always hope for the best as we monitor the breeding efforts of wild birds that we are lucky enough to get to know personally through live-streaming cameras. After extended discussions, including with the landowner hosting the nest box and camera, we continue to adhere to our strict no-interference policy. Below, we summarize why and address several of the most common questions we’re getting.

Purposes of the Bird Cams

We put cameras on bird nests for two very explicit and carefully considered reasons, both of them entirely consistent with the mission of the Cornell Lab. (1) We seek to give everybody with Internet access the chance to watch up-close the very personal details of the lives, behaviors, social relationships, challenges, and successes of birds – not as pets, but as organisms in the wild. (2) We seek to reveal, and to stimulate thinking about, exactly what is required to be a successful individual and a successful breeder in nature.

By putting live cameras on bird nests, our intentions do not include accepting responsibilities for the outcome of the nesting attempt, unless our very own actions begin to cause harm. We respect the fact that other web-cam hosts around the country choose to take a different approach, but our intent is specifically to show how natural processes unfold in the absence of human intervention. To begin caring for the individuals we monitor would immediately negate the explicit purposes (stated above) for which the Cornell Lab undertakes all the considerable trouble and expense of hosting these Bird Cams.

The question of ethics

We do not consider it unethical to supplement or rescue Barn Owl nestlings, and although we will not intervene in natural processes at this nest, we certainly empathize with those viewers who wish we would do so. Likewise, however, we reject the argument that failing to supplement or rescue is unethical. Like many other kinds of birds, Barn Owls and other raptors have evolved a successful strategy for maximizing the number of young they can produce. They lay a large clutch of eggs, and in times of plenty they often succeed in fledging all of them. When times are difficult, either because of a thin prey base or from environmental stressors like bad weather, few or none may survive. Our commitment is to educate people about nature, and to stimulate their thinking about what wild organisms need to do in order to survive and reproduce. Already this cam has shown us many outcomes, including some positive ones, that we might not have predicted if we had chosen to supplement the nest. The Barn Owl camera is accomplishing its objectives, and certainly the many hundreds of social media posts over recent days attest to this – albeit via events and images that many of us find dreadful. There is nothing unethical whatsoever about revealing how difficult it is to be a wild bird.

Bird feeding is intervention, so what’s different about a nest box?

The key distinction is the very different purposes between feeding birds and hosting a camera in a nest box. We feed birds for at least two reasons. (1) Feeding birds allows us to see up-close many of the creatures (often including squirrels, chipmunks, raccoons, etc.) with whom we share our neighborhoods. This brings us pleasure, entertainment, knowledge, and understanding about the daily and annual cycles around us, admittedly facilitated by supplemental food. (2) Feeding birds helps many birds live through tough times, bad weather, and food shortages, thereby increasing the chances that they will live long and successful lives around us. At the Cornell Lab, we put cameras on bird feeders so that others around the world can see them and learn from them. We make no claim that feeders are “natural” – we simply provide opportunities for those who are interested to enjoy and learn from watching those feeders.

While a nest box does supply an ideal home for a territorial pair of Barn Owls in Texas, owls in this area are not limited by nest sites. The region is filled with structures – some human-constructed, many others natural – that are capable of harboring a nesting pair of owls. The box simply supplies a more-or-less predictable environment for hosting a camera in order to reveal what would be occurring in any other nest site of the region. In contrast to bird feeders, the explicit purpose of this enterprise is education about the comings and goings, successes and failures, at a nest of wild birds.

The larger picture

Among the many things we learn from Bird Cams such as this one, we see clearly that wild birds face multiple challenges in nature – in this case, they face bad weather, food shortages, competition, predation, and even starvation when conditions became stringent. Hopefully, such lessons encourage all of us to make decisions in our own lives not to add to their challenges, but instead to keep improving how humanity cares for the natural environments on which our wild birds depend. These owls will live to breed another day, as long as we keep protecting the habitats they require in order to do so.

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Will the Cornell Lab intervene if the nest is abandoned?

June 5, 2016
Given the developments of the past several days, including 24 hours with no prey being brought to the nest and no visit from Dottie, we have received many questions and expressions of concern for the owlet. Additionally, because the owlet has walked out on the ledge a few times recently, people wonder what will happen if it falls out of the nest prematurely. We would like to share with you the contingency plan now in place and the reasoning behind it.

First, please keep in mind that a young owl’s best chance for survival in the wild is to be raised by its parents. The average life span for a Barn Owl in the wild is just 20.9 months. Research has shown that owls that are rehabilitated and released in the wild have even lower survival rates than wild Barn Owls. If a parent is nearby, it is best to allow that parent to continue caring for its young rather than taking it into captivity. We have seen cases, both this year and in previous years, in which a parent returned with food long after the point at which many viewers had assumed the nest was abandoned. Had we intervened in those instances, we would have taken away the opportunity for the owls to be cared for by their own parents and we would not have learned of their extraordinary resilience.

However, if this year’s nest is truly abandoned (that is, if Dottie is dead or unable to function as a parent), the nestling has no chance to survive. In such a case, we will do what we advise all people who have found a potentially abandoned nest: 1) observe the nest to be certain it is abandoned; and 2) if so, call a rehabilitator. (Read more information about abandonment, especially of songbird nests which are often encountered around people’s yards.) We recognize that many people believe this nest to be abandoned already. However, the female has been absent for more than one night in the past, and nestlings have survived even after receiving no prey for several days. For experts in raptor biology, it is still premature to assume this nest has been abandoned. We will give both Dottie and her nestling their best chance to survive in the wild by letting this natural circumstance continue to unfold, but if we determine that the nest is likely abandoned, we are in contact with an local expert rehabilitator who has generously agreed to help if and when the Cornell Lab makes this decision.

Along with all of this cam’s viewers, we hope that Dottie returns with prey, as she has done previously after intervals in which she had been away. We are monitoring the situation constantly, and will continue to provide updates on the Barn Owl cam web page.

We appreciate all of your interest and support.

Thank you.

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Questions and Answers About Texas Barn Owl Events, June 6-7, 2016

Q: Is Dottie back?

A: Although Dottie is not banded, the owl’s plumage is consistent with Dottie’s. Additionally, its behavior is what we would expect for a resident owl. It flew up to the nest box, went in immediately, and appeared to be relaxed, resting, and preening. This is in contrast with the unknown visitor owl last week who would fly by the box quickly, stand on the landing while scanning the area, or go inside the box for brief periods. Because these Barn Owls are not banded, we cannot definitively identify them but our interpretation is that it is likely to be Dottie, and we will answer the remaining questions with the assumption that it is she.

Q: Is Dottie injured?

A: Last week, viewers reported that Dottie appeared to be holding her right wing in a slight droop, possibly indicating a bruise or muscle/ligament strain. However, at the time, she was still able to fly back and forth from the box. The owl today also may have a slight droop in the right wing but flew in and out of the box with no difficulty and showed no signs of distress. We consulted rehabilitator Kathy Rogers who said that because the owl is still able to fly well on its own, there is no need to capture or examine it, and the injury, if any, would be expected to heal on its own.

Q: Will you reunite Dottie and her owlet?

A: The Cornell Lab of Ornithology and Rogers Wildlife Rehabilitation Center agree that under most circumstances a young bird’s best chance for survival is to be raised by its parent. However, for this particular case and this particular individual, the Rogers Rehab Center does not advise returning the owlet to the nest, and the Cornell Lab supports this decision. The owlet had gone without food for several days, so it will take time for her to gain back her full weight and expected condition for her age and stage of development. At this time it is uncertain whether Dottie would provide for her nestling since she had not been bringing in prey for several days. Another consideration is that when avian parents are no longer in the presence of their young, their hormones begin to change, and they may cease providing parental care. After a period of three days away from the nest, we could not predict whether Dottie would continue to care for her nestling. Additionally, there is a possibility that the owl in the box is not Dottie but resembles her. For all these reasons, the owlet will remain at the Rogers Rehab Center until capable of being released on her own.

Q: When the owlet is ready, will it be released into the wild?

A: That is the hope and plan. When young Barn Owls are ready to learn to hunt, Kathy releases them into an enclosure so they can learn to capture live prey. An adult Barn Owl, who itself was rehabilitated but not releasable, serves as a foster parent by being in the enclosure with the young owl. When the young owl successfully captures prey for seven days in a row, Kathy would deem it releasable to the wild and would plan to release the owl near where it was raised.

Q: Why didn’t the Cornell Lab supplement the nest with prey from the beginning so that all six owlets could have survived instead of just one?

A: The Cornell Lab does not intervene at natural events in the nest because the purpose of the cam is to learn from nature as it is, observing birds as their lives unfold in the wild. Our Bird Cams capture not only the beauty of nature but also the significant survival challenges that birds face, including extremes of weather, predation, and starvation. By interfering, we would lose the opportunity to understand the failures and successes of birds when faced with these challenges on their own. For example, we have seen cases, both this year and in previous years, in which a parent returned with food long after the point at which many viewers assumed that the nest had been abandoned. Had we intervened in those instances, we would have taken away the opportunity for the owls to be cared for by their own parents and we would not have learned of their extraordinary resilience. Additionally, supplementing a nest, although providing temporary relief, could create an unsustainable situation at the time of fledging. Dottie–then a single parent–would have had to provide for six juvenile birds, and yet we witnessed that it was difficult enough for her to care for just one. As one viewer stated, although five perished in the nest, no life was wasted as the surviving nestlings gained sustenance by eating their dead siblings during times of food shortage, enabling the number to survive that their parent would be most able to support. For more about why the Lab does not intervene, please read the statement by Cornell Lab director John Fitzpatrick.

Q: Why did the Cornell Lab decide to rescue the owlet on June 6 instead of letting nature take its course?

A: By June 5, the owlet had gone for two days without food and Dottie had been absent for more than a full day. Because we had seen parents return after a period of absence of more than one day, and because we had seen nestlings survive without food for more than two days, we decided to wait another day to see if Dottie would return. If a parent is nearby, it is best to allow that parent to continue caring for its young rather than taking it into captivity. The average life span for a Barn Owl is just 20.9 months and researchers have shown that owls that are rehabilitated and released in the wild have even lower survival rates than wild owls. By June 6, despite clear and favorable weather and hunting conditions, Dottie had not returned for well over two days and the owlet had gone without food for three days. Based on the best available evidence, we made the educated assumption that Dottie was no longer attending the nest as a providing parent. If that were the case, the owlet would have had no chance to survive and streaming the cam would no longer have a purpose. In essence, we made the biological judgement to declare this nesting attempt a failure (i.e., resulting in no fledglings), and thereafter we asked the Rogers Wildlife Rehabilitation Center to rescue the owlet, At that point, we took the cam offline.

Q: Now that an owl is back in the box, will you start streaming again?

A: We would like to start streaming again so that everyone can watch as life at this nest box continues to unfold. At this time we are taking a break to get a breather, process what has happened, and look forward. The past two weeks were stressful and exhausting as our staff worked around the clock to manage the social media furor created by some angry people expressing hostility to the Cornell Lab, Cornell University, cam hosts, and fellow viewers. We are now catching up with and attempting to manage our 9 other cams and 2 more that will be coming online soon. We thank you for your patience while we catch up. We will provide updates on this web page if we note any significant changes at this nest. Meanwhile, we hope you will enjoy other cams or get away from the cams for a while to enjoy watching birds in the outdoors this summer. Subscribe to our free Bird Cams eNewsletter if you’d like to receive updates, including news and announcements about the Barn Owl cam. Thank you for watching with us this season. We hope to see you again soon!

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When will the chicks leave the nest?

Barn Owl chicks usually fledge 50–55 days after hatching.

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When does the chick get adult plumage?

The chicks’ downy feathers are replaced by flight feathers by about 35–65 days of age. By 60 days, feather growth is usually completed, though flight and tail feather growth may take an additional week or two. This plumage looks similar to the adult plumage, but technically, it is considered juvenal plumage. Over the next two or more years, Barn Owls will slowly acquire their official adult plumage.

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Do the parents feed the young birds after they leave the nest?

Barn Owl chicks usually remain dependent on their parents for about 3–5 weeks after fledging. At this time adults will roost away from the nest site and interact with the young only to bring food. However, siblings commonly roost together for many weeks after leaving the nest. The earliest recorded successful prey capture was at 72 days after hatching. Usually the parents stop feeding the young when they are about 12–13 weeks old.

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How do the nestlings get water?

While in the nest, the nestlings get water from the prey that they are fed.

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Why are the Barn Owls panting? Are they too hot?

Barn owls rely on both physiological and behavioral adaptations to handle heat. Roosting and nesting in sheltered nest boxes can play a key role in helping mitigate high temperatures and other environmental conditions that may have a negative impact.

Birds do not have sweat glands and use various different methods to thermo-regulate. We have seen the Texas Barn Owls gular fluttering regularly- the fast opening and closing of the beak. Several bird species vibrate the muscles and bones in their throats helping to cool their airways and lower elevated internal temperatures. The owls can also shunt blood to lightly feathered areas of their bodies, including the beak, toes and legs. The lightly feathered undersides of the owls’ wings can also dissipate heat and drooping the wings helps expose the underside to the air to help them cool. While higher than ambient temperatures could be a potential stressor (95-104 degrees Fahrenheit- higher limit of heat stress) the owls are able to mitigate the effects of heat stress by panting, gular fluttering or by postural thermoregulatory behavior. The zone of thermal indifference (the range of ambient temperatures within which birds do not show specific behaviors to cope with the thermal environment) for owlets is thought to range between 68 and 87 degrees Fahrenheit.

Nest boxes have helped Barn Owl populations recover in areas where natural nest sites were scarce, and in certain areas nest boxes are the only available nesting habitat available to the owls, this particular area of Italy, Texas included. There are many advantages to nesting in a sheltered box- decreased forced convection, less direct exposure to precipitation, wind and solar radiation and higher than ambient temperatures during incubation. The Texas Barn Owls’ nest box is shaded in an open-air pavilion, with at least 7-10ft of space from the roof of the nest box to the roof of the pavilion. The box is also breathable and not air-tight, with a high roof and plenty of space for the owls to move around. While there are no additional ventilation holes outside of the main entrance and the hole for the camera, a study about boxes with and without ventilation holes (performed in FL in full sunlight) suggested that ventilation likely affects internal box temperatures less than 1 degree C. In places that are cold too (like TX in the winter) the lack of ventilation may also be beneficial to holding in heat.

Barn owls have poor insulation due to sparse feathering. With long lightly feathered legs and scanty fat reserves the owls’ are poorly adapted to cold weather and are more suited to southerly North American states. They are particularly vulnerable in severe winter weather. There are advantages for choosing nest sites with higher temperatures, one being the important reduction of maintenance energy of the birds. Owls need to use up metabolic energy from the food they eat to keep warm. If the atmospheric temperature is warm they use less energy, which is a bonus when you are trying to grow feathers. Nesting in sheltered boxes or inside a building can reduce heat production by 21% compared to nesting outside. Annual metabolic heat production has been estimated in one study to be reduced by 19% by roosting inside buildings. If the ambient temperature is below 73 degrees Fahrenheit the owlets need to use metabolic heat production to maintain their core temperatures (this is the lower critical temperature).

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More Facts

Where do Barn Owls live?

Barn Owls are found in many areas of the world. In North America, they live in open habitats across most of the lower 48 United States and extend into a few areas of southern Canada. They may be found in grasslands, deserts, marshes, agricultural fields, strips of forest, woodlots, ranchlands, brushy fields, and suburbs and cities. They nest in tree cavities, caves, and in buildings (often barns but also including Yankee Stadium). In the Andes they occur as high as 13,000 feet. Barn Owls will also often take up residence in nest boxes. Our NestWatch project has construction plans to build nest boxes appropriate for many species, including one sized for Barn Owls.

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How many Barn Owls are there?

Barn Owls are a widespread species, usually living at a low density in open habitat. Partners in Flight estimates a global breeding population of about two million.

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How long do they live?

There are reports of Barn Owls living into their twenties in the wild, but most die before they are two years old. Studies across the world indicate that between 60–85 percent of individuals die in their first year before breeding.

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How many young do they have in their lifetime?

An 18-year study of Barn Owls in Utah documented the lifetime reproductive success for over 260 owls and found that most birds only had one successful breeding season and the mean number of eggs produced in an owl’s lifetime was just under ten. Twelve percent of the females in this study left breeding descendants in the population. After following the descendants for four generations, the direct number of descendants from the original females varied from 3–69. Utah is at the northern edge of these owls’ range and Barn Owls in other locations appear to be more successful breeders.

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The Barn Owls in my area look different than the ones on camera. Why?

There are as many as 46 different races, or subspecies, of Barn Owl worldwide. The North American form is called Tyto alba pratincola and is the largest, weighing more than twice as much as the smallest race from the Galapagos Islands.

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What predators are threats to Barn Owls?

Barn Owls face threats from mammals, birds, and reptiles. Stoats and snakes will prey upon nestlings. Raptors may kill both adults and young birds. Depending on location, avian predators may include the Great Horned Owl, Golden Eagle, Red Kite, goshawks, buzzards, Peregrine Falcon, Lanner Falcon, eagle owls, and Tawny Owl.

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What other dangers do Barn Owls face?

As with many other species, changes to the environment can threaten Barn Owl survival. The conversion of agricultural land to urban and suburban development, and the loss of suitable nesting sites such as large, hollow trees and old buildings have caused a decline in Barn Owl numbers. Changes to agricultural fields and grasslands can also affect Barn Owls through changes to their prey populations. Barn Owls were affected by the use of DDT-related pesticides, and they may be susceptible to poisons used against rodents, since they form a large part of the owls’ diet. Because Barn Owls hunt by flying low over fields, they are often hit by cars; planting hedgerows alongside roads can help prevent this from happening. Nest boxes (take a look at our NestWatch page for Barn Owl nest box plans) have helped Barn Owl populations recover in areas where natural nest sites were scarce, and in certain areas nest boxes are the only available nesting habitat available to the owls. Barn Owls are also very sensitive to cold weather and harsh winters can cause an increase in mortality.

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Do Barn Owls migrate?

It is possible that food supply may trigger some seasonal movement, but generally, Barn Owls do not migrate and will even remain in their most northern habitats. There have been reports of Barn Owls migrating, but it is likely that these are, in fact, reports of young owls dispersing from their natal areas.

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Do the young stay in the same area as the parents after they are independent?

Young Barn Owls will disperse usually starting in the late summer and autumn after they hatch. Some individuals may wander through early winter until they find a suitable site; others may find a roost as early as November where they will eventually breed. Young may disperse just a few miles or as far as 1,200 miles away from their natal nests. Suitable habitat and food supply are probably important factors driving dispersal.

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Are Barn Owls aggressive? How do they attack?

Barn Owls do not appear to be particularly aggressive, though they do defend the immediate area around their nests. If an intruder comes near the nest site, the owls will chase the threat away, even lashing out with their talons. When threatened, Barn Owls give a threat display, spreading their wings and hanging their bodies or heads low while swaying them back and forth. These displays are accompanied by hissing, bill-snapping, and closed eyes. if the attacker persists, the owl may issue a distress scream, fall onto its back and strike with both feet.

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Where can I see a Barn Owl?

Many people’s first sighting of a Barn Owl is while driving through open country at night—if you see a flash of pale wings in the headlights, it is usually this species. Barn Owls also often live up to their name, inhabiting barns and other old, abandoned buildings, so keep an eye out for them there. Barn Owls don’t hoot the way most other owls do; you can listen for their harsh screeches at night.

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What can I do to help Barn Owls?

You can help Barn Owls by being a good steward to the environment. Chose environmentally friendly products when using cleaners and pesticides. Don’t lure Barn Owls into harm’s way by tossing food out near a road; this attracts rodents and raptors may swoop down to capture prey, only to get hit by vehicles.

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Camera

Does the camera bother the birds?

No, the owls usually ignore the camera.

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How long will the camera stay on?

The camera will stream during the entire nesting season.

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What type of camera is being used?

An AXIS P3364-LVE Network Camera. There is also a microphone mounted to the inside of the box. The cam feed is transmitted wirelessly from the nest site to a nearby structure with internet access.

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Why is the nest so bright at night?

The new AXIS P3364-LVE Network Camera has an infrared illuminator and can “see” infrared light. Infrared light is not the same thing as thermal imaging. The view from the camera is not detecting the heat of the owl’s body. What you’re seeing is the infrared light from the camera’s illuminator being reflected off objects in the nest.

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Does the light disturb the birds?

No. Owls cannot see infrared light so the infrared illuminator does not disturb them.

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Comments

  • Karen in CA

    What is the area between the eyes, sometimes it is open sometimes closed..is this a breating area?

  • Karen in CA

    breathing

  • Wendy from Maine

    I saw the barn owls mating this morning with 4 eggs already in the nest. Must they mate to produce each egg, or were they just “fooling around”?