As regular CFZ-watchers will know, for some time Corinna has been doing a column for Animals & Men and a regular segment on On The Track... particularly about out-of-place birds and rare vagrants. There seem to be more and more bird stories from all over the world hitting the news these days so, to make room for them all - and to give them all equal and worthy coverage - she has set up this new blog to cover all things feathery and Fortean.

Friday 10 August 2018

Flycatchers follow the rain


13/07/2018

Understanding what environmental cues birds use to time their annual migrations and decide where to settle is crucial for predicting how they'll be affected by a shifting climate.

A new study from The Auk: Ornithological Advances shows that for two species of tyrant flycatcher, one of the key factors is rain – the more precipitation an area receives, the more likely the birds are to be there during the non-breeding season.

Tulane University's Maggie MacPherson and her colleagues combined field techniques with species distribution models to investigate which environmental factors drove the migrations of Eastern Kingbirds and Fork-tailed Flycatchers. Using geolocators, devices that record a bird's daily location based on day length, they could track where individuals of each species went. The two species share similar behaviour and habitat requirements, but differ in their range and migration strategies, and these strategies were compared to determine the influence of temperature, precipitation and primary productivity (that is, the amount of 'green' vegetation). Precipitation turned out to be one of the most important predictors of their distribution, particularly in the non-breeding season.


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