Baseline and Stress‐Induced Levels of Corticosterone during Different Life Cycle Substages in a Shorebird on the High Arctic Breeding Grounds

Abstract

Baseline and stress-induced levels of corticosterone during different life cycle substages in a shorebird on the high arctic breeding grounds Reneerkens, J; Morrison, RIG; Ramenofsky, M; Piersma, Theun; Wingfield, JC Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. ABSTRACT After a migratory flight of several thousand kilometers to their high arctic breeding grounds, red knots (Calidris canutus islandica, Scolopacidae) showed high baseline concentrations of plasma corticosterone (58 ng/mL). Such high baseline corticosterone levels may be conditional for the right behavioral and metabolic adjustments to environmental and social stresses that shorebirds experience on arrival in an unpredictable tundra breeding environment. Despite the high baseline levels of corticosterone, red knots still showed a marked stress response during the postarrival period, with corticosterone concentrations increasing significantly during a 60-min period of confinement. Baseline levels of corticosterone declined as the breeding season progressed. Red knots with brood patches, that is, birds that had completed egg laying and commenced incubation, had a reduced adrenocortical response to the stress of confinement compared with red knots with no, or with halfdeveloped, brood patches. This is consistent with the idea that birds breeding in extreme environments with short breeding seasons may exhibit a decreased adrenocortical response to

Are birds stressed during long-term flights? A wind-tunnel study on circulating corticosterone in the red knot

“…The average baseline corticosterone concentration of the red knots in our study (15.7 before and 14.00 ng/ml after the experimental flights, see Fig. 1) is within the range reported in other studies on the same species (10-30 ng/ml; Piersma and Ramenofsky, 1998;Reneerkens et al, 2002). Hence, it seems very unlikely, that the baseline levels were affected by the immune challenge the knots experienced before the flight experiments (Hasselquist et al, 2007).…”

“…Elevated baseline levels of corticosterone have been observed in several species during the migratory period at rest and just after endurance flight, when the birds have landed (O'Reilly and Wingfield, 1995;Holberton et al, 1996;Landys-Ciannelli et al, 2002;Reneerkens et al, 2002). It is hypothesized that during a phase of increased energy demands hormone action maintains the metabolism within a heightened operating range, defined as state B by McEwen and Wingfield (2003).…”

Long flights do not influence immune responses of a long-distance migrant bird: a wind-tunnel experiment

“…These birds also had no elevated corticosterone, except in a few which had completely emaciated breast muscles and no visible fat. The baseline corticosterone values of all birds in our study were very similar to those of wild red knots at their breeding grounds (Reneerkens et al, 2002) and to apparently unstressed red knots that had long been adjusted to living in indoor cages . Similarly low values were found in refuelling bar-tailed godwits Limosa lapponica Linnaeus in the wild (Landys-Ciannelli et al, 2002), whereas red knots and godwits newly arrived following long flights had substantially higher corticosterone levels (Reneerkens et al, 2002;LandysCiannelli et al, 2002).…”

Role of the Low‐Affinity Glucocorticoid Receptor in the Regulation of Behavior and Energy Metabolism in the Migratory Red KnotCalidris canutus islandica

“…Birds were removed from aviaries once every week so that aviaries could be cleaned and were weighed and checked for general health status at this time. Piersma et al (2000) and Reneerkens et al (2002) suggested that corticosterone levels in migrating red knots increase specifically in association with migratory flight. To corroborate these findings, we first investigated plasma levels of corticosterone in captive birds during spring migration (May-June) in the year 2000.…”

“…For example, when held in captivity on their wintering grounds, red knots show an increase in plasma corticosterone only after having attained a body mass similar to that of departing conspecifics (Piersma et al 2000). Also, free-living red knots display elevated corticosterone at the conclusion of a long bout of migratory flight, as they arrive at their breeding grounds in the North American Arctic (Reneerkens et al 2002). The correlation between corticosterone and migratory flight in this species suggests that corticosterone may be involved in the onset and regulation of migratory movements and correlated physiological processes.…”