Cheating Chickadees Choose Males with Better Spatial Awareness

Female mountain chickadees that cheat on their partners consistently choose males with superior spatial memory, according to new research by American scientists.

Psychologist and biologist Carrie Branch and her colleagues have been studying the behavior of Gambel's chickadees in California's Sierra Nevada since 2018. The team fitted the birds with tiny leg rings containing chips and installed special bird feeders with motorized doors. Initially all doors opened, but gradually only some did.

Birds that quickly learned to access the correct door demonstrated better spatial memory - they remember where food is cached and are considered smarter.

DNA analysis of nestlings revealed that over 30% of chicks were fathered by a male other than the mother's partner, and over 70% of nests contained at least one extra-pair offspring. Eggs fathered by smarter males were heavily dominant and their offspring were heavier.

Remarkably, females that performed worse on the memory test were more likely to have extra-pair young in their nests, suggesting they compensate for their own cognitive shortcomings by seeking smarter fathers.

Good spatial memory is critical for these birds. Living in cold mountainous regions, they must cache food in multiple locations. Birds that best remember these locations have a significantly better chance of survival.