The Large Ground Finch (Geospiza magnirostris)

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Large ground finch pair

Large ground finch pair

Today we’re talking about a challenging past #BeakoftheWeek nominee, the large ground finch. As the name suggests this species has a rather large bill relative to its body size and is often as deep as it is long.  You can see why it has been charmingly nicknamed ‘Megamouth’.

Amongst the most famous groups of birds in the world, this species has the honour of being one of Darwin’s finches. Here is a nice brief recap on Darwin’s finches, and a great little graphic showing their different bill shapes and diet.  This clip talks about them further whilst showing some of the different species.

Endemic to the Galapagos Islands off of the West coast of Ecuador, they are found in arid scrub and lowland areas on many of the islands. .

These birds use their big beaks to feed on caterpillars, fruits and large seeds.  Males are almost entirely black with slightly browner wings and tail, and females are dark brown with sandy-buff fringing. They are about 15cm long and weigh around 35g.

Large ground finch male

Large ground finch male

This species is usually monogamous and tend to mate after the first rains of the season. Nest building is carried out by the male who constructs a sphere made from dry grass and other vegetation with a lateral entrance near the top.  The pair can lay up to 4 clutches in one season, which usually consists of 4 eggs that take about 12 days to hatch.  The nestlings leave the nest after around 14 days.

This species is of least concern on the IUCN redlist, and population numbers are said to be stable.

Xeno Canto has a solitary song for them, and you can reacquaint yourself with exactly where the Galapagos Islands are by following the link.

References

BirdLife International 2012. Geospiza magnirostris. The IUCN Red List of Threatened Species. Version 2015.2. <www.iucnredlist.org>. Downloaded on 06 July 2015.

BirdLife International (2015) Species factsheet: Geospiza magnirostris. Downloaded from http://www.birdlife.org on 07/07/2015

Jaramillo, A. & Christie, D.A. (2013). Large Ground-finch (Geospiza magnirostris). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.) (2013). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/62175 on 6 July 2015).

. 2010. Large Ground-Finch (Geospiza magnirostris), Neotropical Birds Online (T. S. Schulenberg, Editor). Ithaca: Cornell Lab of Ornithology; retrieved from Neotropical Birds Online: http://neotropical.birds.cornell.edu/portal/species/overview?p_p_spp=632076

Images

Large ground finch male” by Gerald and Buff Corsi is licensed under CC BY-NC-SA 3.0.

Large ground finch pair” by John Gould is licensed under Public Domain Mark 1.0.