Yellow-crowned Night-Heron Life History

Habitat

Habitat MarshesYellow-crowned Night-Herons breed in and near wetlands primarily in the southeast United States, in areas of abundant crustaceans. Although concentrated on the southern Atlantic Coast, they are regularly found inland as far north as Ohio, Wisconsin, and Minnesota, and sometimes appear in Michigan and Ontario. Their breeding habitat includes barrier islands, coastal lowlands, inland lowlands, forests with open understories, mangroves, and edges of lagoons. In coastal areas they forage along the edges of tidal marshes, tide pools, calm beaches, and lagoons. Inland, they forage along shallow creeks, rivers, ponds, lakes, and swamps, and occasionally on lawns, plowed fields, and other upland sites. After the breeding season many individuals disperse to the north and west before migrating to wintering grounds. They stay year-round along the coastal edge of their U.S. breeding range, in locations where the climate permits crab activity throughout the year.Back to top

Food

Food Aquatic invertebratesYellow-crowned Night-Herons feed primarily on freshwater and saltwater crustaceans, including marsh crabs, fiddler crabs, ghost crabs, mole crabs, mud crabs, blue crabs, lady crabs, green crabs, rock crabs, and toad crabs. In inland areas they feed almost exclusively on crayfish. They also eat smaller amounts of earthworms, leeches, marine worms, centipedes, snails, mussels, insects, scorpions, frogs, tadpoles, marine fish, freshwater fish, small snakes, turtles, young birds, and small mammals. Standing still or walking slowly, they forage within several feet of the water’s edge, separated from other foraging individuals by about 15 feet. When within striking distance of prey they lunge with their bills, swallowing smaller animals whole. They grab larger crabs by the legs or pincers and shake them apart, then swallow the pieces whole or use their bills to break them further. They may also impale crabs, paralyzing them to make them easier to handle.Back to top

Nesting

Nest Placement

Nest TreeYellow-crowned Night-Herons nest near or over water in trees such as pine and oak—as high as 60 feet or more off the ground—or on lower vegetation such as mulberry, myrtle, hackberry, and mangrove. On islands with limited vegetation, they may nest on rock ledges. The male chooses the location, and the pair may start several nests before completing one. They nest alone or in colonies of up to several hundred pairs, sometimes with other heron species. Some colony sites remain in use for more than 20 years.

Nest Description

The nest, a platform of sticks with a slight hollow in the center, can measure more than 4 feet across. The male and female build it together as part of their pair bonding. Initially, the male carries sticks to the female, who begins the nest. Later, both gather and place materials on the nest. Where possible, they strip sticks from the limbs of dead trees rather than gathering them from the ground. Sticks can be up to about 20 inches long and an inch thick. The twig nest is sometimes lined with leaves, vines, or Spanish moss. The building process averages about 10 days. Night-herons may reuse nests, adding to them each year, or refurbish vacant ones.

Nesting Facts
Clutch Size:2-6 eggs
Egg Length:1.8-2.2 in (4.6-5.7 cm)
Egg Width:1.2-1.5 in (3-3.7 cm)
Incubation Period:24-25 days
Nestling Period:30-43 days
Egg Description:Pale bluish green.
Condition at Hatching:Helpless, covered in white or pale gray down, with eyes open after 1 day.
Back to top

Behavior

Behavior StalkingYellow-crowned Night-Herons usually walk slowly, using a bent-over posture when foraging, and fly with slow wingbeats. Courting Yellow-crowned Night-Herons perform display flights, along with a neck-stretching display: the male slowly raises and then quickly retracts his head while fanning his long shoulder plumes. The female will sometimes reciprocate. They form socially monogamous pairs, and some maintain their bonds from year to year. Pairs may nest close together, but both adults and young defend the site from intruders, lunging and jabbing with their bills while squawking. Older young may peck or trample younger siblings and even push them out of the nest. After the breeding season, young birds often disperse to the north or west before heading to wintering grounds. Back to top

Conservation

Conservation Low ConcernYellow-crowned Night Herons are fairly numerous, but their population trends are hard to assess because they nesting birds can be hard to see during large standardized surveys. The North American Breeding Bird Survey identified no statistically significant change in their population between 1966 and 2014, although trends suggest a decline. Their population has fluctuated in the last century or so: after shrinking southward in the 19th century, the species expanded northward dramatically in the early 20th century before retreating again slightly after 1950. The reasons for these fluctuations are unclear. The North American Waterbird Conservation Plan rates them at least a 12 out of 20 on the Continental Concern Score and lists them as a Species of Moderate Concern. They are not on the 2014 State of the Birds Watch List, though they are protected in some states near the edge of their range. Like all wetland birds they are vulnerable to habitat loss or degradation. Historically, Yellow-crowned Night-Herons were hunted as food or for their plumes. In residential areas where herons nest over houses, roads, and driveways, human residents sometimes disturb the nesting birds on purpose to drive them away.Back to top

Credits

Dunne, P. (2006). Pete Dunne's essential field guide companion. Houghton Mifflin Harcourt, New York, USA.

Kushlan, J. A., M. J. Steinkamp, K. C. Parsons, J. Capp, M. A. Cruz, M. Coulter, I. Davidson, L. Dickson, N. Edelson, R. Elliott, R. M. Erwin, S. Hatch, S. Kress, R. Milko, S. Miller, K. Mills, R. Paul, R. Phillips, J. E. Saliva, W. Sydeman, J. Trapp, J. Wheeler and K. Wohl (2002). Waterbird conservation for the Americas: The North American waterbird conservation plan, version 1. Washington, DC, USA. 

Lutmerding, J. A. and A. S. Love. Longevity records of North American birds. Version 2015.2. Patuxent Wildlife Research Center, Bird Banding Laboratory 2015.

North American Bird Conservation Initiative. 2014. The State of the Birds 2014 Report. US Department of Interior, Washington, DC, USA.

Sibley, D. A. (2014). The Sibley guide to birds, second edition. Alfred A. Knopf, New York, USA.

Watts, Bryan D. 2011. Yellow-crowned Night-Heron (Nyctanassa violacea), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Back to top