Some birds better than others at adjusting to habitat degradation

August 30, 2017

Before habitat degradation from impacts like grazing begins to cause population declines, the first response by wildlife usually comes in the form of behavioral changes—for example, switching their diets in response to changes in food availability. A new study from The Condor: Ornithological Applications looks at the diets of seed-eating birds in a South American desert and finds that while some can switch between seed types when grazing alters local plant communities, others continue to stick to old favorites, limiting their options.

Luis Marone of the Argentine Arid Zones Research Institute (IADIZA-CONICET) and his colleagues collected soil samples at grazed and ungrazed sites in Argentina's Monte Desert to assess the composition of the seed bank in each area, finding fewer of the large grass seeds that birds prefer in the grazed areas. Flushing the digestive tracts of captured birds revealed that two seed generalists, Common Diuca-Finch and Rufous-collared Sparrow, adjusted their diet accordingly and ate more forb seeds at grazed sites, while grass seed specialists Many-colored Chaco Finch and Ringed Warbling-Finch did not.

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