BLUE TITS USE FLEDGLING QUANTITY AND QUALITY AS PUBLIC INFORMATION IN BREEDING SITE CHOICE

• DOI: 10.1890/06-2000.1
• Publication Date: 2007-09-13T21:17:35Z
• Authors: Deseada Parejo; Joel White; Jean Clobert; Amelie Dreiss; Etienne Danchin
• Keywords: Male; 0106 biological sciences; resident birds; [SDE.MCG]Environmental Sciences/Global Changes; components of public information; Blue Tit; Animals, Wild; Environment; breeding habitat selection; 01 natural sciences; Nesting Behavior; Birds; Cyanistes caeruleus; Animals; performance-based cues; dispersal; Probability; Behavior, Animal; Reproduction; [SDV.EE.IEO] Life Sciences [q-bio]/Ecology, environment/Symbiosis; [SDE.BE] Environmental Sciences/Biodiversity and Ecology; [SDE.MCG] Environmental Sciences/Global Changes; birds; emigration; Animal Migration; Female; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; Cues; habitat copying; immigration; [SDV.EE.IEO]Life Sciences [q-bio]/Ecology, environment/Symbiosis

Public information (PI), which is the information that can be derived from the behavior and performance of conspecifics, has been demonstrated to be used in many fitness-enhancing decisions. In the context of breeding habitat choice, PI use has been called "habitat copying." We experimentally tested the existence of habitat copying in the Blue Tit (Cyanistes caeruleus), a nonmigratory, short-lived hole-nesting bird. We manipulated the mean number of fledglings raised locally (quantity) and their condition (quality) as components of PI by transferring nestlings from Decreased (D) patches to Increased (I) patches. Our manipulations caused a negative relationship between fledgling quantity and quality that does not exist naturally: I patches had a higher number of fledglings that were in poorer condition, whereas D patches had a lower number in better condition. Control (C) patches, whether manipulated or not, had intermediate levels in terms of fledgling quantity and quality. Adult emigration the following year was higher from D than from C or I patches. Similarly, adult dispersal distance decreased for individuals coming from D to C to I patches. This suggests that resident breeders rely mainly on fledgling quantity to make emigration decisions. Emigration patterns of juveniles did not vary in relation to our patch manipulation. Immigration rates were higher and similar in I and D patches than in C patches. Hence, immigrant Blue Tits seem to rely on one of the manipulated components of PI and are insensitive to the discrepancy between fledgling quantity and quality. This shows that even nonmigratory species, such as Blue Tits, may use PI in their dispersal decisions but weigh its components differently for emigration and immigration. Differences among species in the importance of PI in breeding habitat choices may be explained by differences in life histories.