The 2018 field season was an outstanding success, with progress made on four major research themes that included (1) continued collection of data on cliff swallow reproductive success at 47 different colonies (a new record for number of colonies studied!) to examine the importance of fluctuating selection on colony size; (2) continuation of the fumigation experiments to measure the effect of swallow bugs on cliff swallow nesting success, as a comparison to similar data collected in the 1980’s; (3) continuation of personality studies on cliff swallows to measure how risk-taking and boldness varies among birds in different sized colonies; and (4) studies of foraging ecology, both behavior and diet, to investigate how the birds’ social foraging strategies may have changed since the 1980’s. We continue to be amazed at the differences in cliff swallow nesting ecology that we see now compared to the 1980’s. This year was unusual in that it was both warm and wet, a climatic combination that is rare in our study area. The birds probably had better than average food resources, and this may have been the reason why we saw a much larger incidence in late nesting attempts in 2018 than usual. It appears that this year's late nests were also more successful than is typical. We speculate that while late nesting is usually unsuccessful, the occasional "good" year like this one may result in enough fitness gain to select for birds who try to nest late. A number of birds appeared to have done true "second" broods this year, that is, attempted a second clutch in the same nest where they fledged babies earlier in the season.
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