The Effects of Investigator Disturbance on Nesting White-Tailed Hawks in South Texas
No Thumbnail Available
Date
2022-04-15
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The white-tailed hawk (Geranoaetus albicaudatus) is a common raptor located throughout Central and South America. Only one subspecies of white-tailed hawk, G. a. hypospodius, is known to live as far north as the coastal regions of Texas. Despite being classified as a state-threatened species in Texas, little is known about the white-tailed hawk’s life history and population demographics. The lack of information about the white-tailed hawk makes it challenging to identify how to protect and manage the species. The few studies done on this species in the past indicate that white-tailed hawks are sensitive to anthropogenic disturbances. Additionally, the white-tailed hawks’ nesting locations within Texas (grasslands, savannahs, pastures) are becoming increasingly threatened and fragmented. Information pertaining to impacts of nesting disturbance and nesting success could be essential in protecting the animal’s natural populations. In my study, I quantified nesting disturbance activities and their impacts on nesting white-tailed hawks, specifically by focusing on whether adults will avoid their nests and young for greater amounts of time following researcher approach. This behavior could decrease nestling success by leaving them vulnerable and without parental care for more extended periods. To learn more about the white-tailed hawk’s disturbance reactions, I measured the amount of time the adults leave the nest following researcher approach and investigate possible impacts. I used data collected from footage captured by motion-activated cameras placed at white-tailed hawk nests throughout several different locations in south Texas during the 2021 breeding season. Preliminary analysis focused on the nest located on Mustang Island State Park in Nueces County, Texas, where over 5,000 minutes of footage was reviewed in total. The average length of time that the adult white-tailed hawks spent away from their nest following an investigator disturbance event (116 mins) was significantly longer than time spent away from the nest for any other reason on days with (46.9 mins) and without (44 mins) a disturbance event. The total amount of time that both adults were absent from their nest also increased on days with (64.5 % of recorded daylight hours) and without (57.8% of recorded daylight hours) a disturbance event. Establishing buffer zones around white-tailed hawk nests during their nesting season may be an effective way to protect their populations in the coastal bend region of Texas.
Description
Keywords
white-tailed hawk, conservation, nesting behavior, birds of prey