Male birds tend to assist their parents less than females because they focus on finding new habitats for living and breeding, according to a fascinating new study.
A fascinating new study reveals that male birds assist their parents less than females due to their preoccupation with searching for new places to live and breed.
This research, conducted by the Centre for Ecology and Conservation at the University of Exeter, explored how white-browed sparrow weavers—social birds residing in the Kalahari desert—behave cooperatively and how they move.
White-browed sparrow weavers form family units where typically only one dominant pair breeds, and their mature offspring, especially females, play a significant role in feeding the chicks.
The purpose of this new study was to investigate why in many species, one sex tends to contribute more to family support than the other.
“Female sparrow-weavers play a larger part in caring for the nestlings than males and tend to remain with their family groups longer,” explained Dr. Pablo Capilla-Lasheras, who conducted the study during his PhD at Exeter and is now affiliated with the Swiss Ornithological Institute.
“We aimed to uncover the reasons behind these differences in cooperative behavior between sexes in the animal kingdom.”
“The prevailing theory suggests that the sex that resides longer in family groups is more cooperative since they benefit from their contributions for an extended period.”
“For instance, those who stay longer in their family can receive more assistance in return from family members they have previously helped, compared to those who depart sooner.”
After more than ten years of field research on the cooperative behaviors of these birds and an innovative study monitoring their movements, the researchers’ findings indicate otherwise.
“Our outcomes suggest a different explanation that has received less attention,” remarked Dr. Andrew Young, who heads the Kalahari sparrow-weaver project.
“It appears that males assist less because they dedicate more time to seeking potential places for living and breeding elsewhere, thereby balancing this with their efforts to help at home.”
Given these insights, the team proposes that the ‘dispersal trade-off hypothesis’ may offer a broader understanding of the evolution of sex-based differences in cooperation throughout the animal kingdom. This contrasts with the traditional belief that “the longer you stay, the more you benefit from your contributions.”
This trade-off exemplifies a common challenge faced by all living beings, including humans; there’s never enough time or resources to excel in every aspect simultaneously.
This study was supported by funding from the Natural Environment Research Council and the Biotechnology and Biological Sciences Research Council.
