Food availability is expressed through physiological stress indicators in nestling white ibis: A food supplementation experiment

Functional Ecology
By: , and 



1.Physiological responses to environmental stress such as adrenocortical hormones and cellular stress proteins have recently emerged as potentially powerful tools for investigating physiological effects of avian food limitation. However, little is known about the physiological stress responses of free‐living nestling birds to environmental variation in food availability.

2. We experimentally tested how hydrologically mediated changes in food availability affect the physiological stress responses of juvenile white ibises Eudocimus albus in a fluctuating wetland. We provided supplementary food to free‐living nestlings during 2 years with contrasting hydrologic and food availability conditions, and used plasma (PCORT) and faecal (FCORT) corticosterone and heat shock proteins (HSP60 and HSP70) from first‐hatched (A‐nestlings) and second‐hatched (B‐nestlings) to detect relatively short‐ to long‐term responses to food limitation.

3. Nestling physiological stress responses were relatively low in all treatments during the year with optimal food availability, but PCORT, FCORT and HSP60 levels increased during the poor food year. FCORT and HSP60 responses were clearly due to nutritional condition as elevated concentrations were evident primarily in control nestlings. Significant year by hatch order interactions for both FCORT and HSP60 revealed that these increases were largely incurred by B‐nestlings. FCORT and HSP60 responses were also well developed early in neonatal development and remained elevated for the duration of the experiment suggesting a chronic stress response. PCORT and HSP70 were less informative stress responses.

4. The nutritionally mediated increases in FCORT and HSP60 provide compelling evidence that white ibis nestlings can be physiologically affected by environmental food levels. FCORT and HSP60 are effective indicators of nutritional mediated stress for nestling white ibises and potentially for other species prone to capture or handling stress.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Food availability is expressed through physiological stress indicators in nestling white ibis: A food supplementation experiment
Series title Functional Ecology
DOI 10.1111/j.1365-2435.2010.01792.x
Volume 25
Issue 3
Year Published 2011
Language English
Publisher British Ecological Society
Contributing office(s) Forest and Rangeland Ecosys Science Center
Description 9 p.
First page 682
Last page 690
Country United States
State Florida
Other Geospatial Arthur R. Marshall Loxahatchee National Wildlife Refuge
Google Analytic Metrics Metrics page
Additional publication details