Corticosterone and growth hormone levels in shorebirds during spring and fall migration stopover

Abstract

Large numbers of shorebirds stop over at Delaware Bay during spring migration and undergo major mass increases within a two‐ to three‐week period. We studied plasma levels of corticosterone and growth hormone in three species of migrants that use this site, sanderlings, Calidris alba, semipalmated plovers, Charadrius semipalmatus, and semipalmated sandpipers, Calidris pusilla. Semipalmated sandpipers were also studied at a fall migration stopover in Manomet, Massachusetts. These two hormones were chosen because they modulate the physiological processes of lipogenesis/lipolysis and promote increased feeding in birds. The stress response was not suppressed in the shorebirds studied, and plasma levels of corticosterone were elevated compared to other studies. We believe that the high levels of corticosterone relate to the rapid fat deposition that takes place at this stop‐over site. There was a significant negative correlation between plasma growth hormone and body mass, indicating the lipolytic effects of the growth hormone. Because the lighter birds are recent arrivals to Delaware Bay they may have elevated plasma growth because of fat breakdown during flight to this stop‐over site. High levels of growth hormone may also result in protein synthesis, replenishing tissues broken down during the previous migratory bout. J. Exp. Zool. 284:645–651, 1999. © 1999 Wiley‐Liss, Inc.

Plasma Corticosterone Levels of Semipalmated Sandpiper Calidris pusilla Overwintering in a Tropical Coastal Lagoon of Northeastern Venezuela

“…In this preliminary work, even if we have not applied a classical protocol of capture‐handling stress, variations observed in plasma corticosterone related to the time of capture were similar to that found by Tsipoura et al 15 . for the same species.…”

Circadian Corticosterone Profile in Laying Hens (Gallus gallus domesticus)

“…The role of CORT in reproduction has not yet been clearly defined. On the one hand, there are studies that indicate a negative influence of CORT on breeding behavior in favor of foraging [ 71 , 72 ]. Other studies show that increased plasma CORT concentrations increase foraging in parents and, consequently, lead to increased body weight in chicks, providing a fitness advantage [ 73 ].…”

Physiological parameters of a plover during nonbreeding and breeding seasons in Patagonia, Argentina

“…Other studies, for example in gulls, reported values of H/L about 0.6 in normal individuals compared to 2.9 in birds that were affected by stressors such as oiling, emaciation, injury, or parasite infection (Averbeck 1992). Some migratory shorebird species have shown differences in haematological and biochemical parameters between sexes (e.g., Tsipoura et al 1999, Landy-Ciannelli et al 2002, D'Amico et al 2017, Valdebenito et al 2021. However, for TBPLs results showed no differences between sexes neither during nonbreeding nor breeding (Fig.…”