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Herons,­Egrets,­and Bitterns

Megan Shaw Prelinger, Jennifer Linander, and Rebecca S. Duerr

Natural History

There are 65 species of herons, egrets, and bitterns in the family Ardeidae within the order
Pelecaniformes, and 10 species of herons and egrets are found in North America. All species of
herons and egrets nest in trees, although some may occasionally nest on the ground in treeless
areas. All species have semi‐altricial, downy chicks that hatch with their eyes open. Herons and
egrets are colonial nesters and typically hatch groups of nestlings at the rate of two to four per nest.
Incubation lasts 17–28 days, depending on the size of the species, and young are fully flighted by
7–8 weeks. Some species may continue to support fledglings for a short period after they have left
the nest (Parsons and Master 2000; Hothem et al. 2010; McCrimmon et al. 2011; Vennesland and
Butler 2011).
Herons and egrets have anisodactyl feet, with three long toes pointing forward and one pointing
back, with partial webbing between digits 3 and 4. Each toe is furnished with a sharp and pointed
claw. The remarkable length and hensile strength of their toes and the sharpness of their claws
enable them to firmly grip tree branches of varying thicknesses.
Adult diets are adaptable to available food stocks. Small fish and aquatic invertebrates are pre-
ferred foods, although all herons and egrets rely additionally in varying measures on small rodents
and insects. Young are fed a regurgitated diet for their first few days of life, but they readily learn
to pick up foods left for them on the floors of their nests.

­ Criteria­for Intervention

Herons and egrets are gregarious colonial nesters that are less sensitive to human population den-
sity than some other families of birds. Many young fall from nests in their early days or weeks of
life. Fallen young hatched in colonies that are situated in remote environments may climb back up
to nests or be fed on the ground by their parents while they hide in surrounding grasses, and slowly
learn to feed themselves. Fallen chicks hatched in urban or suburban colonies, however, are
extremely vulnerable to predators such as birds of prey, cars, cats, and dogs, because such colonies
tend to be situated above cropped grass or pavement rather than above tall natural undergrowth.
Fallen nestlings are thus left entirely exposed, and may be miles away from an appropriate habitat.
Some species normally fledge from the nest prior to being capable of flight, but this may be

Hand-Rearing Birds, Second Edition. Edited by Rebecca S. Duerr and Laurie J. Gage.
© 2020 John Wiley & Sons, Inc. Published 2020 by John Wiley & Sons, Inc.