Effects of research disturbance on nest survival in a mixed colony of waterbirds

Abstract

Background Long-term research is crucial for the conservation and development of knowledge in ecology; however, it is essential to quantify and minimize any negative effects associated with research to gather reliable and representative long-term monitoring data. In colonial bird species, chicks are often marked with coded bands in order to assess demographic parameters of the population. Banding chicks in multi-species colonies is challenging because it involves disturbances to species that are at different stages of progress in their reproduction. Methods We took advantage of a long term banding program launched on Glossy Ibis (Plegadis falcinellus) breeding in a major mixed colony of herons in Camargue, southern France, to assess the effect of banding operation disturbance on the reproductive success of the three most numerous waterbirds species in the colony. Over two breeding seasons (2015 and 2016), 336 nests of Glossy Ibis, Little Egrets (Egretta garzetta) and Cattle Egrets (Bubulcus ibis) were monitored from a floating blind in two zones of the colony: one zone disturbed twice a year by the banding activities and another not disturbed (control zone). We applied a logistic-exposure analysis method to estimate the daily survival rate (DSR) of nests and chicks aged up to three weeks. Results Daily survival rate of Glossy Ibis was reduced in the disturbed zone while DSR increased for Little and Cattle Egrets in the disturbed zone. Nevertheless, DSR was not reduced on the week following the banding, thus discarding a direct effect of handling on breeding success of Glossy Ibis. The protocol and statistical analysis presented here are robust and can be applied to any bird species to test for the effect of a research disturbance or other short and repeated temporal events that may affect reproductive success over one or more breeding seasons.

Drones as a tool to study and monitor endangered Grey Crowned Cranes (Balearica regulorum): Behavioural responses and recommended guidelines

“…The most common method for collecting breeding metrics at crane nest sites is by utilising lengthy, physical on‐foot observations to identify breeding cues followed by wading to nest sites (Wamiti et al., 2020 ; Wen et al., 2021 ). This method can be unreliable and invasive (Zelelew et al., 2019 ), potentially disturbing breeding activities through nest abandonment and creating direct pathways to the nest sites for natural predators (Champagnon et al., 2019 ; Coverdale, 2006 ; Francis et al., 2022 ; Wamiti et al., 2020 , 2022 ). The nesting preference of GCCs and ineffective monitoring methods have resulted in major knowledge gaps in GCC ecology and reproductive success, hindering the development of effective conservation strategies.…”

Curves for Curlew: Identifying Curlew breeding status from GPS tracking data

“…Terrain and cryptic behaviors can make this almost impossible for some species (Brown & Shepherd, 1993 ; Valle & Scarton, 2019 ). In addition, such monitoring carries a risk of disturbance and therefore potential impacts on breeding outcomes (Champagnon et al, 2019 ; Götmark, 1992 ; Syrová et al, 2020 ). Fortunately, the rapid development of remote tracking studies provides an alternative means of monitoring species' behaviors at all stages of their life cycles (McKinnon & Love, 2018 ).…”