Dependence of the azure-winged magpie on nest spatial cues in offspring recognition decreases with nestling growth

Various cues have been identified as the basis for animals’ discrimination
between kin and non-kin. In altricial birds, these cues show temporal and
spatial variations, implying that kin recognition might be
condition-dependent. In this study, we hypothesize that parents might be
sensitive to the changes in nest spatial position, and that their
dependence on the nest spatial cue in offspring recognition decreases with
offspring growth. We tested this hypothesis in a Tibetan population of the
azure-winged magpie, Cyanopica cyanus, by designing a nest translocation
experiment. We found that adults could return to their nest and continue
caring for their offspring even if the nest had been moved to a new
position. Their sensitivity to the spatial change in nest position not
only varied with distance but also relied on the offspring life-history
stage. Breeders were more likely to recognize their nest and offspring
during the nestling period than during the incubation period, indicating
that the dependence of parents on the spatial cue of the nest is higher
when offspring are in the form of eggs than in the form of nestlings. Our
findings suggest that azure-winged magpies mainly depend on the spatial
position of the nest to recognize their nest and offspring. After
nestlings establish communication with their parents, their phenotypic
characteristics may replace the nests’ spatial cue to play a greater role
in the offspring recognition of parents.