Found on every continent except Antarctica and Australia, the Black-crowned Night Heron is the most widespread heron in the world.  Local distributin of Black-crowned Night Herons is determined by suitable wetland habitat for foraging.An opportunistic forager, the black-crowned prefers shallow, weedy pond margins, creeks and marshes but on the coast will use levee cordgrass, mudflats exterior to Spartina marshes, tidal creeks, tidal ditches, and piling and boat riggings.  Though it feeds in the same areas as other herons, the Black-crowned Night Heron is active primarily at dusk and during the night. 

In Texas, the largest concentrations of the species are found on the coast, with 80-90% of the breeding population is concentrated in coastal areas.  Most nesting sites are likely chosen for predator avoidance. Most colonies are found on islands, in swamps or over water. They nest in colonial groups, either in single species or in large multi-species rookeries.  Black-crowned Night Herons use a very wide variety of vegetation as nesting substrate and nest height average varies widely by location: nest heights ranging between 1.1 meters and 14 meters have been recorded. The species has been noted to prey on other bird species, especially nestlings of other colonial waterbirds in the rookery in which they nest.

For more information on Black-crowned Night Herons, including identification tips, visit their page on the Cornell Lab of Ornithology. 

Text References

1. Hothem, R. L., B. E. Brussee, and W. E. Davis Jr. 2010. Black-crowned Night-Heron (Nycticorax nycticorax).in A. Poole, editor. The Birds of North America Online Cornell Lab of Ornithology, Ithaca.
2. Telfair II, R. C. 2007. Black-crowned Night-Heron. The Texas Breeding Bird Atlas. Texas A&M University System, College Station and Corpus Christi, TX.