Natal legacies cause social and spatial marginalization during dispersal

Area of Science:

• Behavioral Ecology
• Wildlife Ecology
• Animal Social Networks

Background:

• Early-life conditions significantly influence individual social behaviors.
• The mechanisms by which developmental conditions shape social network position remain unclear.
• Understanding these pathways is crucial for comprehending population structure.

Purpose of the Study:

• To investigate how developmental conditions affect social network position in early-dispersing wild red kites (Milvus milvus).
• To explore the role of competition and resource availability in shaping social interactions post-fledging.

Main Methods:

• Combined experimental food supplementation with GPS tracking of 211 juvenile red kites from 140 broods.
• Analyzed social encounters and spatial distribution using 4425 bird-days of GPS data.
• Compared social network metrics and habitat use between control and supplemented groups.

Main Results:

• Last-hatched chicks, identified as less competitive, had fewer peer encounters post-fledging.
• Food supplementation increased social encounters for less competitive individuals.
• Less competitive kites dispersed to marginal areas when resources were scarce but aggregated in central areas when food was supplemented.

Conclusions:

• Early-life adversities create lasting behavioral legacies that extend beyond independence.
• Individual responses to competition and resource availability are key drivers of social and spatial structure.
• These findings have significant implications for the social dynamics and spatial organization of animal populations.