Temperature and rainfall shape the breeding ecology of Barn Swallows Hirundo rustica in an arid region

Local weather conditions play a critical role in shaping avian
reproduction, yet our understanding of these patterns in arid
environments, where climate change is expected to increase drought
frequency, is limited. This study investigated the effects of temperature,
rainfall, and wind speed on the breeding ecology of Barn Swallows (Hirundo
rustica) in an arid region of Algeria during 2023 and 2024. Using
generalized linear mixed models (GLMMs), we assessed these effects for
several life-history traits and breeding parameters including clutch size,
incubation duration, hatching success, nestling period duration, and
reproductive success. Our results indicate that clutch size decreased
seasonally, while incubation duration increased with rainfall and was
shorter for second clutches. Hatching success correlated positively with
the amount of precipitation and was higher in second clutches. Nestling
period duration increased both seasonally and with prolonged incubation.
Reproductive success benefited from greater rainfall but declined as the
season progressed and when incubation was extended. Additionally, higher
temperatures reduced renesting probability, suggesting that heat may limit
Barn Swallows’ reproductive efforts. Our results highlight the importance
of rainfall in shaping reproductive success and reveal the negative impact
of high temperatures on the breeding performance of Barn Swallows in this
region. In a context of climate change and increasing drought frequency,
these findings underscore the challenges that Barn Swallow populations
might face in arid environments in the near future.