Nest density, egg conspicuity, vegetation structure and seasonality affect artificial nest predation in the Brazilian Cerrado

Aguiar, Ivan R. de; Vianna, Vinícius Rozendo; Dias, Raphael Igor

doi:10.1017/s0266467422000268

Cited by 1 publication

(1 citation statement)

References 76 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The nest-predation rate varied substantially and significantly during the breeding season, with the highest nest-predation rate in the middle of the breeding season. This result is in accordance with hypothesis 1 and with the results of some other investigations [35][36][37][38][39]97] but not with the majority of investigations referred to in the Introduction [21][22][23]42,43]. These studies show that there is a high diversity in nest-predation rates during the breeding season in different areas, probably because a range of ecological factors also vary during the season and influence the nest-predation rate.…”

Section: Discussionsupporting

confidence: 88%

Experiments Reveal That Search Image Might Be Responsible for Seasonal Variation in Nest-Predation Rates

Husby,

Verdal

2024

Diversity

View full text Add to dashboard Cite

Investigations of seasonal variations in nest predation rates yield highly variable results. Some investigations argue that search image is responsible for some of the nest-predation patterns, but as far as we know, this study is the first in which search image in connection with seasonal variation in nest-predation rate has been experimentally tested. We used 1457 artificial nests placed in an identical way during the months of March to August, either in the two months consecutively or early and late within one of the two months, between the years 2000 and 2023. In addition, we compared the change in nest-predation rates at 113 artificial and 460 natural nests between the same two months. We estimated the seasonal variation in the abundance of breeding birds in the study area with 140 point counts to find the abundance of different species at the times when they normally breed. We found a strong and consistent seasonal variation in the nest-predation rate, with the highest predation rate in the middle of the breeding season. There was a similar change in the predation rate on natural and artificial nests between May and June. From July to August, the predation rate on artificial nests decreased significantly, while the search-image experiment revealed a significant increase between the same two months. A generalized linear mixed-effect model analysis found that the variation in nest-predation rates on artificial nests was significantly affected by seasonal variation in the estimated number of natural nests, that nests in trees were predated more often than nests on the ground, and that nests in the open landscape and on forest edges suffered higher predation rates than nests inside a forest. Mammals were nest predators significantly more often inside forests and on forest edges than in the open landscape, but birds were much more common nest predators than mammals independent of placement and habitat. Our experiment shows that search image explains the seasonal variation in nest-predation rates. However, more investigations are needed to find the reasons for the variation in published results on seasonal variation. Further, experimental testing on search image to find its contribution to the seasonal variation in nest-predation rates in other areas is also needed.

show abstract