Breeding biology of the threatened Campo Miner Geositta poeciloptera (Aves: Scleruridae), a Neotropical grassland specialist

ABSTRACT

The Campo Miner is a threatened grassland passerine endemic to the South American Cerrado, whose life history is almost unknown. In this paper, we studied during three breeding seasons (2014 to 2016) the breeding biology of a colour banded population of the species found in the Upper Rio Grande Grasslands, south-eastern Brazil. We found 98 nests, 81 of which became active and were monitored. The Campo Miner breeds in frequently burnt-and-grazed natural grasslands, successfully nesting in highly disturbed sites, such as dirt banks along roads and even in mine pits. The species is socially monogamous and both parents build the nest, which is a cavity/with-tunnel/simple/platform type. The nest chamber is lined with a platform made of grass fragments, charcoal, hairs, and mammal faeces. The most common clutch size is three eggs (n = 66), with some nests containing one (n = 1), two (n = 12) or four eggs (n = 2). The egg is white and pyriform and the incubation, performed by both parents, lasts 17.5 days. Mean nestling period is 15.5 days, with both parents feeding the young. Breeding season lasted for about 125 days (August to December) and multiple breeding attempts in a single season were common, with a maximum of three attempts recorded. All species of Scleruridae built their nests inside cavities dug in the soil with an access tunnel to it, where they lay a small clutch (usually 2–3 white eggs), but no other species in the family has been studied in detail to date. Further studies are required to understand why a species apparently tolerant to anthropogenic impacts such as G. poeciloptera can be so rare, patchily distributed and threatened throughout its range.

KEYWORDS:

• Brazil
• cavity nest
• Cerrado
• conservation

Acknowledgements

TLSSM, RCM and JPGT received MSc fellowships from CAPES. All procedures performed in this study involving animals were in accordance with the ethical standards of the institution or practice at which the studies were conducted, with permits provided by CEMAVE/ICMBio (3923/1) and CEUA-UFV (227/2015). We thank the several farmers who allowed our studies in their properties. Manoel Machado, Marina Silva, Jéssica Reis, Carol Pereira, Manoel Souza, Dalila Ferreira, Reinaldo Araújo, Laís Silva, Michelle Baptista, Wesley Davies, Villányi Peter, Antônio Marcos, Gustavo Gonzaga, and Libério Silva helped during fieldwork.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the CNPq [grant numbers 476031/2013-3 and 305401/20149].