The Nature Writers of Texas

The best nature writing from the newspaper, magazine, blog and book authors of the Lone Star State . . .

Sunday, July 31, 2005

Cross Timbers Wildlife News
Night Ravens

Jim Dillard, Wildlife Biologist, Texas Parks & Wildlife Department, Mineral Wells

I couldn’t begin to tell you how many roadside wildlife surveys I’ve conducted over the years for Texas Parks and Wildlife on everything from road-killed armadillos to ringtails. Most surveys involve early morning or late evening drives along established routes on back roads to record observations of game or in some cases nongame wildlife species. Some counts are made at night when species like white-tailed deer or opossums are most active and more likely to be observed. Invariably, some critter other than the one for which the surveys was intended to enumerate is encountered. Such was the case a number of years back as I made an early morning roadside pheasant brood count up in the Texas Panhandle north of Dumas.

As I stopped on the side of a dusty section-line road to flush a brood of pheasants from the bar ditch, incessant squawking sounds caught my attention. They were coming from a large grove of cottonwood and willow trees that surrounded an irrigation tail-water pit at the edge of a big corn field. Large birds were flying in and out of the trees and alighting in a fresh plowed field nearby. When I finished the survey route, I returned to the spot to check out the source of all the commotion.

What I discovered was a rookery of black-crowned night herons in various stages of nest construction, egg laying, incubation and rearing of young. They were not pleased with me poking around under their colony and let me know about it with loud scolding squawks. I learned rather quickly not to look up when they flew off their nests. They really freaked when I crawled up in the trees with them to take a few photos up close and personal of their nests and babies. Black-crowned night heron babies are truly those only a black-crowned night heron mommy could love. I took a few photos and left them to their squabbling and squawking.

The black-crowned night heron (Nycticorax nycticorax) is one of two species of this group of herons found in Texas and the one most common here in the Cross Timbers. Its scientific name Nycticorax means “night raven”, a moniker often associated with this species for the raven-like call made during their nighttime foraging. It’s best described as a loud quock or quaik. In Hawaii, they’re called aukuu. The yellow-crowned night heron (Nyctanassa violacea) is more common in East Texas and the southeastern United States. Black-crowns are found worldwide except in Antarctica and Australia. In the U.S., they migrate from the northern portion of their range to spend the winter in coastal areas.

Black-crowned night herons have relatively short yellow legs and a stocky or hunched profile without the characteristic long neck of other heron species. Feather coloration on their head and back is black; wings are pale gray and breast feathers lighter gray or white. Two or three long white flowing plumes extend from the back of the head of adults and their eyes are red. I’ll never forget those bright red eyes peering at me through the rustling leaves of a cottonwood tree years ago as I clumsily climbed into that rookery. Juveniles have brown plumage on their head, back and wings with white spots and brown streaking on their light colored breasts. Adult plumage is not acquired for about a year and they may not breed until they’re two or three.

Black-crowned night herons may nest in isolated colonies or in colonial rookeries with other species of herons and egrets. Females build a flimsy platform nest precariously place at the forks of tree limbs and branches. It’s constructed of small sticks and then lined with grass or other soft materials brought to her by the male – it’s her way or no way. There she’ll lay three to five pale blue eggs that are incubated by both of them for 24-26 days. Young are fed regurgitated food items (yuck!) by both parents for another 28 days before fledging at 42 days. They’ll begin to crawl about and explore on limbs around their nest when about three weeks of age. While they’re still flightless, young black-crowns are known to be aggressive and will regurgitate or defecate on intruders, including an unsuspecting wildlife biologist (been there – done that!).

As their common name implies, they’re most active late in the evening and into the night. It’s during this time they hunt for their prey around aquatic habitats such as marshes, rivers, ponds, swamps and other wet areas. Foods of choice include small fish, frogs and other amphibians, crustaceans, insects, snakes, rodents, mussels and even carrion. Along the coasts, they’ll feed on squid, clams, small birds, bird eggs, crabs and invertebrates. During the nesting season, they may be seen forage during the day to satisfy the voracious appetite of their nestlings.

They usually hunt by standing still or walking slowly along shorelines or in shallow water, snatching their prey with a rapid thrust of their neck and stout bill. Food items are securely held in their dark serrated bill and then flipped for proper orientation for swallowing whole. Their strong digestive acids dissolve even bones, turning them into limy white feces. Unlike other herons, they can swim well and may light on water or dive headfirst after prey. Some black-crowns have even learned to hang out around well lighted shorelines of ponds and lakes in urban areas for their nocturnal hunting forays.

Night ravens are only one of many critters that go quank in the night and make you jump and wonder, from the security of your tent or sleeping bag, what’s out there – is it coming closer or going the other way. Just shut your eyes and listen for the night raven and unless you hear one saying “NEVERMORE - NEVERMORE” – all is well in the Cross Timbers. Until next time, I’ll see you down the road and God Bless America!


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