About the Dunrovin Osprey Nest
These Ospreys are nesting amid the hustle and bustle of Dunrovin Guest Ranch in Lolo, Montana. During the past 10 years they have fledged 1–3 young per year, first on a telephone pole and now on a new platform and pole installed by Northwestern Energy in 2011. Neither of the adults is banded, but they are thought to be the same pair given their easy habituation to daily ranch activities. If you look carefully, you can probably tell the male from the female by her more heavily streaked chest.
Ospreys are consummate fishing birds, and this pair fishes both from a nearby pond as well as the Bitterroot River. They use their 6-7 foot long wingspan to soar above the water, looking for fish, then diving as deep as 3 feet for shallow-swimming prey. Adult Ospreys usually weigh 3–4 pounds, and they can carry prey up to 50 percent of their own weight. Ospreys can live up to 25 years, and they typically lay 1–4 eggs in a clutch.
Most Osprey pairs are monogamous, staying paired across seasons and beginning nesting soon after each returns from a long migration. Both sexes incubate the eggs. The female sits for the majority of the time (including throughout the night) while the male provisions her with fish. After the eggs hatch, the male continues to bring fish to the nest; the female exclusively broods the young and dissects their meals for about a month after hatching. Later on, when the chicks no longer require her protection and their appetite for fish increases, she will leave the nest and go fishing. For more details about the Dunrovin Ranch Ospreys and ways to further connect with them please visit The West's Best Nest.
Learn more about Opsreys in our species guide.
2012 Breeding Details
This year the pair started incubating around April 23, and two eggs have been confirmed in the nest. Incubation lasts 6–7 weeks, so the first chick should hatch in late May or early June. Young will hatch asynchronously, with the second chick appearing 2–5 days after the first. During years of low food supply, a distinct size difference may develop between the two early on, with the smaller chick usually catching up later. Once the young have hatched, it's another 7–9 weeks until they fledge. Just before the chicks leave the nest, researchers from the University of Montana will band the young and take blood samples as part of a long-term study on mercury in the environment (see "About the Study" below).
About the Study
For the past five years, Dr. Erick Greene and Dr. Heiko Langner from the University of Montana, and Rob Domenech from the Raptor View Research Institute, have studied Ospreys in western Montana, including these birds at Dunrovin Guest Ranch. They’re learning about the health of local rivers by studying what the Ospreys bring back to the nest and feed their chicks. For this research they are employing a number of video cameras on Osprey nests, two of which are viewable online. They recently received a grant from the Natural Resource Damage Program to continue public education and research involving the local Ospreys.
Because of their top position in the food web, Ospreys are useful indicators of local environmental conditions. Young Ospreys eat only fish their parents catch within a few miles of the nest, so these young birds reflect the condition of the local fish population. And although many hawk species can be touchy—even dangerous—to work with, Ospreys make good subjects: they tolerate human activity well and they actually seek out human-made structures to use as nest platforms. Researchers plan to band and collect small feather and blood samples from the nestlings before they fledge.
Osprey populations declined to near-extinction in the Lower 48 States after World War II as a consequence of exposure to DDT-based pesticides. The dwindling Osprey population helped trigger research into problems with DDT, resulting in its ban in the United States in 1972. Since then, Ospreys have returned to many large water bodies. Studies such as this one help scientists keep a watchful eye on how Ospreys—and the water bodies they depend on—are doing.
Every summer when the chicks are big enough, the researchers band the chicks, take very small blood and feather samples. These samples are analyzed for environmental toxins in Dr. Heiko Langner’s lab. The good news is that levels of some heavy metals of particular concern (lead, arsenic, cadmium, lead and zinc) occur at very low levels in Osprey chicks in western Montana. The bad news is that we have found that levels of mercury, a powerful neurotoxin, is at extremely high levels in Osprey chicks in some places. Fortunately, the chicks in this Dunrovin nest have had low levels of mercury for the past five years. We have discovered that about 20 miles away, Opsreys living along the Clark Fork River have unacceptably high levels of mercury. Our research is now focusing on this serious environmental problem.
About Dunrovin Guest Ranch
The mission of Dunrovin Guest Ranch is to enrich lives by providing unique and educational experiences which promote individual learning and cultivate a connection with nature through the lens of the outdoors, the arts, and partnership with the animal world—particularly horses. The owners, SuzAnne and Sterling Miller, consider the Ospreys an integral part of their ranch, engaging their family as well as the surrounding community. They hope that hosting this live cam will create an even greater community of people interested in learning about these incredible birds and further deepen that connection with the natural world.
Learn more about Ospreys in the Cornell Lab's All About Birds species guide
Cam resources for educators
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