In large ASYNC broods, the penultimate and last-hatched chicks frequently died (Fig.
Parrotlet nestlings from SYNC broods reached asymptotic masses averaging 1.5 g less than nestlings from ASYNC broods, suggesting that they were of lower quality.
Parrotlet chicks from SYNC broods fledged at masses averaging 0.8 g less than chicks from ASYNC broods.
The most likely explanation for the differences in resighting rates was irregular resightings of SYNC young: a greater proportion of SYNC young than ASYNC young were missed in their 1st yr of life but resighted in later years.
But a greater proportion of ASYNC females than SYNC females were later found breeding within the study site.
A high proportion of later hatched chicks in large ASYNC broods died with empty crops.
Thus, the starvation of later hatched chicks in ASYNC broods appeared to be due to the inequitable distribution of food among broodmates, rather than to the inability of parents to provide enough food.
Although providing supplemental food to last-hatched chicks in large ASYNC broods increased their probability of survival, they still experienced significantly higher mortality than early-hatched chicks (Fig.
Later hatched nestlings that survived in ASYNC broods did grow more slowly and fledged at a later age than earlier hatched nestmates However, later hatched nestlings generally were heavier at fledging than their nestmates.
Parents attending SYNC broods did not provision their broods at significantly higher rates than parents of ASYNC broods (Fig.
Males that raised SYNC broods were less likely to be resighted than males that raised ASYNC broods (Table 11).
We detected no significant differences in future reproductive efforts of parents that raised experimental ASYNC and SYNC broods.