by J.C. Senar
It is generally recognized that pointed wings allow a faster flight than rounded wings and hence, this shape has been favoured in migrating species or subpopulations. On the other side, rounded wings allow more manoeuvrability, being favoured in closed habitats.
In the last 100 years, eastern North America has experienced extensive clear-cutting in boreal areas, while afforestation has occurred in most temperate areas. This provided André Desrochers with a unique ‘‘natural experiment’’ with which to examine contemporany evolutionary change in birds in response to habitat loss and fragmentation. Using museum specimens he found that over the last century, species mostly found in boreal areas, with increased habitat fragmentation and hence increased need for movement, have evolved more pointed wings. On the contrary, species associated with temperate mature forests, with increased afforestation and hence relaxed selection for mobility, have evolved more rounded wings.
My point of view: The paper, published in Ecology, is outstanding because it provides nice data on the ability of bird species to respond to rapidly changing environments. These are good news for a world where things are changing at a so high rate. The paper is also interesting because makes us to realise that museum specimens remain a relatively untapped data source for studies which need of large data sets obtained over long data series.
Desrochers, A. (2010). Morphological response of songbirds to 100 years of landscape change in North America Ecology, 91 (6), 1577-1582 DOI: 10.1890/09-2202.1