Breeding biology of the endangered Yellow Cardinal Gubernatrix cristata in Brazil

Christian Beier,Carla Suertegaray Fontana

doi:10.1007/bf03544446

Christian Beier, Carla Suertegaray Fontana

Open Access

https://doi.org/10.1007/bf03544446

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Abstract

The Yellow Cardinal, Gubernatrix cristata, has a small geographic range in Brazil, Uruguay, and Argentina. We studied the natural history of the only known Brazilian population of this “Endangered” species (∼50 individuals), which is socially monogamous and may breed cooperatively. During two breeding seasons (October to February 2013–2015), we monitored nests and described the main breeding traits. The breeding season started from the first week of October, with a peak of active nests in mid-November and lasted until mid-February. We found 32 nests, of which 30 were monitored. Female built the open-cup nests in six days (n = 1). All nests were built on Prosopis trees, on average at 2.4 m from the ground. Modal clutch size was three eggs (n = 19), and female incubated for 13 days on average (n = 7). Hatching rate was 76% and nestlings fledged after 16 days (n = 6). Nestling survival rate was 67% with mean productivity of 1.6 fledglings/successful nest. Shiny Cowbird, Molothrus bonariensis, parasitized nests of the Yellow Cardinal, with a frequency of 67% and intensity of 1.9 egg per parasitized nest (1–4 eggs; n = 13). Parasitism in nestlings by botfly larvae (Philornis sp.) occurred in 33% of nests with nestlings. Nest predation was the main cause of nest losses (73%) and we recorded a Geoffroy’s Cat, Leopardus geoffroyi, preying on a nest with eggs. The probability of success using the Program MARK was 13%. Fledgling survival rate during the first month outside the nest was 62% (8/13 fledglings). We found a longer breeding season, occurrence of second broods, and higher rates but fewer nest losses due to brood parasitism in comparison to the Argentinian population. We highlight the importance of natural history studies for the conservation of different populations of the same species.

Highlights

The Yellow Cardinal, Gubernatrix cristata, is a passerine that was more abundant in the past and have a very fragmented distribution through northeast Argentina, Uruguay and southern Brazil (Ridgely & Tudor 2009)
We studied the breeding biology of the Yellow Cardinal from October through February (2013–2015), since nesting activity has not been recorded before October in a previous pilot study
Of the 30 remaining nests, six were found during nest-building, eight during egg laying, 13 during incubation, and three nests with nestlings. Both individuals of the pair were marked in 13 nests, only the male was marked in 13 nests and in four nests only the female was marked

Summary

Introduction

The Yellow Cardinal, Gubernatrix cristata, is a passerine that was more abundant in the past and have a very fragmented distribution through northeast Argentina, Uruguay and southern Brazil (Ridgely & Tudor 2009). There is at least one established resident population in the Rio Grande do Sul with less than 50 individuals (Martins-Ferreira et al 2013, Beier et al 2017). Bird trapping and habitat loss led to a drastic population decline of the Yellow Cardinal in all its range (Dias 2008, Ridgely & Tudor 2009, Azpiroz et al 2012, Martins-Ferreira et al 2013). Studies of breeding biology and life-history comparisons between populations enable early identification of threats, even before any evident population decline occur (Martin & Geupel 1993). Domínguez et al (2015) published the first study of the breeding biology of a Yellow Cardinal population in Corrientes province, Argentina. Some potential threats to breeding cardinals are nest predation, brood parasitism, botfly parasitism (Domínguez et al 2015), hybridization (Bertonatti & López-Guerra 1997), and endogamy (Beier et al 2017)

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