Maternal androgens in black-headed gull ( Larus ridibundus ) eggs: consequences for chick development

Maternal androgens in black-headed gull (Larus ridibundus) eggs: consequences for chick development.

We tested the hypothesis that mother birds counterbalance the negative effects of hatching asynchrony for later-hatched chicks by increasing the yolk androgen concentrations in consecutive eggs of their clutch. In doing so, they may adaptively tune each offspring's competitive ability and, thus, growth and survival. However, evidence in support of this hypothesis is contradictory. The yolk conc...

Analysis of body mass changes in the Black-Headed Gull (Larus ridibundus) during the winter

During the autumn migration of many waterfowls, body mass is lowest upon arrival at the wintering area and gradually increases during the winter. Consequently, body mass is highest before the spring migration. We studied the pattern of body mass changes in the Black-Headed Gull (Larus ridibundus) from December 2010 to December 2016 in the Shinhama area of Chiba, Japan. Based on 327 captured ani...

Maternal yolk androgens stimulate territorial behaviour in black-headed gull chicks.

Avian eggs contain substantial amounts of maternal androgens. The concentrations of these yolk androgens are affected by the maternal environment, such as the level of social competition, parasite exposure or food conditions. Since yolk androgens have been shown to affect a wide array of offspring traits, they may adjust the chicks to the expected post-hatching environment, but experimental evi...

Prenatal androgen exposure modulates cellular and humoral immune function of black-headed gull chicks.

Avian eggs contain considerable amounts of maternal yolk androgens, which have been shown to beneficially influence the physiology and behaviour of the chick. As androgens may suppress immune functions, they may also entail costs for the chick. This is particularly relevant for colonial species, such as the black-headed gull (Larus ridibundus), in which the aggregation of large numbers of birds...

University of Groningen Multiple pathways of maternal effects in black-headed gull eggs