Are roads and traffic sources of physiological stress for the Florida scrub-jay?
Gina M. Morgan A B D , Travis E. Wilcoxen A C , Michelle A. Rensel A and Stephan J. Schoech A
+ Author Affiliations
- Author Affiliations
A Department of Biological Sciences, University of Memphis, 3774 Walker Avenue, Memphis, TN 38152, USA.
B NorthShore University Health System, 1001 University Place, Evanston, IL 60201, USA.
C Biology Department, Millikin University, 1184 West Main Street, Decatur, IL 62522, USA.
D Corresponding author. Email: ginammorgan@gmail.com
Wildlife Research 39(4) 301-310 https://doi.org/10.1071/WR11029
Submitted: 10 February 2011 Accepted: 3 February 2012 Published: 8 May 2012
Abstract
Context: Anthropogenic disturbances induce physiological and behavioural responses in numerous species. The negative effects of human disturbance are of special concern to threatened and endangered species.
Aims: The present study aims to compare physiological stress measures and reproductive success of Florida scrub-jays (Aphelocoma coerulescens) living near roads with jays that live away from roads. Specifically, it aims to test whether roads are stressful.
Methods: We assessed physiological measures that can serve as indicators of ‘stress’ to determine whether a highway that bisects our study site had physiological effects on adult male Florida scrub-jays. We captured male breeders from three territory types, including scrub habitat that (1) bordered a highway with a grassy shoulder that created an ‘edge’ habitat (roadside), (2) bordered human-maintained habitat (a plowed firebreak of sand with adjacent pasture) that served as a control for the edge-effect of the road (pasture) and (3) contained only natural scrub habitat (interior). We measured baseline concentrations of the stress hormone corticosterone (CORT), body mass, and a suite of longitudinal body measures to generate a body condition index in males from each territory type over three breeding seasons.
Key results: Roadside jays had greater body mass than did interior and pasture jays, although there were no differences in overall baseline CORT concentrations or body condition among territory classes. There was no difference in clutch initiation date or size and nestling and independent-young survival.
Conclusions: Our results suggest that the road through our study site has physiological effects on Florida scrub-jays; however, there is mixed evidence as to whether it acts as a chronic stressor.
Implications: Our findings provide evidence that roads and road-associated disturbance has neutral or potentially beneficial physiological effects of roads on Florida scrub-jays. Knowledge of these effects of roads and disturbance on jays will hopefully provide additional opportunities to improve conservation of this species.
Additional keywords: anthropogenic disturbance, corticosterone, condition.
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