Wednesday, April 9, 2014

Texas Barn Owls

http://www.livestream.com/texasbarnowls

About this nest
This Barn Owl box is nestled in the rafters of a large open-air pavilion on a ranch in Texas. Surrounded by grasslands and scrubby forest, the box has been occupied off-and-on by Barn Owls for as long as the landowner can recall. The Cornell Lab previously featured this nest site online from 2005-11, during which time resident owls had 11 nesting attempts, 7 of which successfully fledged at least one nestling. The camera system was updated in 2013, and a pair of owls arrived at the box during the last week of February 2014.In addition to the Barn Owls, other birds of the open grasslands can be heard vocalizing in the background, including Eastern Phoebes, Tufted Titmice, Eastern Bluebirds, and Western Meadowlarks.

About the Barn Owls

Little is known about the two Barn Owls who have taken up residence in this owl box. In 2013 a pair successfully fledged four young owls from this site and those same adults may have returned again in 2014. During the day the owls rest and preen, leaving to forage as night approaches. Listen for their eerie, raspy vocalizations throughout the day and keep track of their comings and goings throughout the night thanks to the infrared illuminator in the box (don't worry-the light is invisible to the owls.)

Barn Owls are more sexually dimorphic than other owl species. The female is larger than the male, with a heavily spotted chest and more color on her head and body; in contrast, the male appears very white and pale. She creates the simple nest cup of shredded regurgitated pellets in which she'll lay an average of 2-18 eggs and the male brings meals of small mammals for her and the nestlings. The female incubates the eggs as soon as they are laid, leading to "hatching asynchrony," a situation where there are big differences in size between the nestlings based upon the hatch date of each. In years of scarcity, the smallest perish and are sometimes even consumed by their nest mates. Though nest failures such as this are difficult to watch, this strategy enables the parents to produce as many young as conditions allow.

Acknowledgments

Thanks to the landowners, who wish to remain anonymous, for allowing us access to this nest and to the property manager for helping to maintain the camera during the season.