Abstract:
Several factors influencing reproductive success were investigated
at a Common Tern colony at Port Colborne, Ontario in 1976. In general
three egg clutches hatched better than two egg clutches and early
started clutches hatched eggs and fledged chicks better than late
clutches; the fledging success of two and three egg clutches was similar.
Early clutches took longer to hatch and hatched more synchronously
than did late clutches. While hatching success differed with nesting
substrate used fledging success' did not* No relationship was found
between either incubation attentiveness and reproductive success or
between incubation attentiveness and clutch size* At no time did
food availability appear to be a factor limiting the successful
upbringing of two chick broods. While fCf chicks (i.e. chicks hatching
from the last laid eggs of three egg clutches) generally survived and
grew poorly relative to their brood mates they grew best when they
originated from clutches that hatched relatively asynchronously.
