Weather fluctuations are linked to nesting success and renesting decisions in saffron finches

Abstract

Life-histories of neotropical birds seem to vary beyond what is expected according to patterns from northern temperate regions. This variation is well exemplified by saffron finches Sicalis flaveola in subtropical Brazil. They breed for five months on a climate that is relatively warm and rainy throughout the year. Females may attempt from one nest with two eggs up to three nests with five eggs per season. Previous work showed that age and individual quality were insufficient to explain variation in their breeding traits. Thus, other factors may still influence reproductive traits of investment and productivity in females. We asked 1) whether breeding traits of individual females were related to temperature and rain from previous weeks, and 2) whether fluctuations in weather during nest phases influenced egg and nestling survival. We monitored 237 nests of 70 marked females for four years. We found that the odds of a female starting a subsequent nest increased when temperatures on the preceding 15-6 weeks were low. Nest success decreased alongside the temperatures before laying dates. The odds of eggs surviving until hatching increased when weather was cold and rainy during incubation. There was no correlation between past weather and laying dates, clutch sizes, egg or nestling masses, incubation periods or number of fledglings per nest. The adverse effects of warmer temperatures and the survival benefit of increased rainfall are surprising and contrary to other birds' patterns. The mechanisms that link weather to renesting probability and nest success in saffron finches are still unknown, and we give some suggestions about their nature. We advocate that further studies with this widespread species might provide further insights into the variability of life-histories in the region.

Quantitative analysis of the orientation of white stork nestlings’ parents from video monitoring

“…Further observations coupled with meteorological data, from a station by the webcam for example, are required to draw statistically relevant conclusions for the species, also linking it to the breeding success, but this study offers a first insight on the question of orientation in the nest. Such studies, on weather influence on breeding success, have for instance recently been conducted for other species such as tits or finches (Gullett et al 2015, Marques-Santos and Dingemanse 2020, Marques-Santos et al 2021. Experiments in captivity would also be an asset to better understanding the role of wind for instance.…”