Dinopium woodpeckers in Sri Lanka have lower fecundity and higher survival than temperate woodpeckers and delayed plumage maturation in both sexes
Tropical birds have smaller clutch sizes than temperate birds, but adult survival is more complex with substantial overlap between tropical
songbirds and temperate songbirds. We use nine species of temperate woodpeckers in North American and Europe and two species of tropical
Dinopium woodpeckers and their hybrids in Sri Lanka to examine the extensive relationship between clutch size and survival. Seventeen adult Dinopium
woodpeckers were color-banded in 2015 and 16 resighted in the breeding season in 2016 for a survival estimate of 0.94. We inspected five Dinopium nests and five family groups for clutch size, for an estimate of 2.5
eggs. The tropical-temperate comparison of clutch size and survival of woodpeckers reveals that tropical woodpeckers have smaller clutch
size and higher survival with no overlap with temperate woodpeckers. Intense study allowed us to age the tropical woodpeckers by
comparing digitized images of orbital feathers surrounding the eye and document delayed plumage maturation in both sexes of second-year
birds. Both sexes of after-second-year birds had larger orbital feathers, but males had larger feathers leading to sexual dimorphism.
We detected no difference in clutch size or survival of hybrids compared with parental forms.