Intraspecific variation in length of incubation period of Avocets Recurvirostra avosetta.

This paper investigates factors influencing the intraspecific variability of incubation periods in Avocets Recurvirostra avosetta. The length of the incubation period of 278 clutches ranged from 19 to 34 days with an average of 23.1 days. Incubation period was influenced by clutch size. There was a seasonal decrease in incubation period resulting in a difference of 1.7 days between the earliest and the latest clutches. The seasonal trend could not be explained by ambient temperature. No relationships could be found between incubation period and colony size, nest density, or habitat. There were significant positive correlations between incubation period and bill length and foot length of the neonates. The possibility that incubation period is influenced by a trade-off between egg and chick mortality rates and embryonic and chick growth rates is discussed

Hoetker H., ARDEA 86 (1): 33-41