The role of reed management and habitat quality on brood parasitism and chick survival of the brood parasitic Common Cuckoo

Abstract

Despite efforts on ecosystem restoration and management, biodiversity loss remains one of the major environmental concerns of our time. Beyond the focus on threatened species, animals that indicate regional biodiversity hotspots and population trends, such as brood parasites, should also be targeted by conservation actions. We studied how reed habitat quality and management influence brood parasitism rate and offspring survival in Common Cuckoos Cuculus canorus parasitizing nests of Great Reed Warblers Acrocephalus arundinaceus in six reed habitats in an intensive agricultural landscape. Data collected from 45 sites over 13 years showed that the brood parasitism rate was highest on large canals and was positively influenced by the availability of potential perches (Cuckoo vantage points) and the height where host nests were built. Cuckoo chick survival decreased with water depth and was not affected by other factors. Our results suggest that the habitat‐dependent detectability of host nests was central in brood parasitism rate and that water level was central in Cuckoo chick survival. Our study shows that a maintenance of intermediate water levels is the most optimal for maintaining Cuckoo populations in intensive agricultural landscapes. Because brood parasites are excellent bioindicators as their presence predicts regional hotspots of taxonomic and functional diversity as well as population trends in bird communities, knowledge on their habitat requirements is relevant in management targeting diverse bird communities.

Reuse of nests in the Great Reed Warbler Acrocephalus arundinaceus: A behavior to save time and energy and to deter nest parasites?

“…The reuse of the nest and the laying of new eggs among the old eggs may be similarly explained as in the case of MP, i.e., to save time and energy. In addition, we believe that in this case the high pressure of brood parasitism by Cuckoos in the VBC (parasitism rate c. 40%, Mérő et al, in revision), also played a role. In highly parasitized populations, Great Reed Warblers tend to develop strategies such as egg recognition and ejection to defend against brood parasitism (Moskát et al, 2008).…”

Human disturbance affects distribution but not nesting success of the Great Reed Warbler in a semi-urban reed habitat

“…Urban-associated habitat alteration increased brood parasitism rates in the Acadian Flycatcher Empidonax virescens nests by the Brown-headed Cowbirds Molothrus ater, indicating that habitat characteristics and configuration in the vicinity of host nests (e.g. potential perches, Mérő et al 2023b) increase the possibility of brood parasitism in urbanized habitats (Rodewald 2009). We believe that brood parasitism remained at the same level in both study periods because the forest belt and availability of shrubs as potential perches for Cuckoos (Moskát & Honza 2000) on the higher parts of the bank changed only negligibly during the entire study period.…”

A Bird’s-Eye View of Chromosomic Evolution in the Class Aves

“…Birds are social, with varying degrees of communication complexity including the use of calls and song (in some cases communicating by visual display); they can be socially cooperative, exhibiting behaviors such as flocking and mobbing. Most birds also provide an extended period of parental care that is often shared between parents and/or with other birds [4][5][6].…”