Fragmentation linked to stress in birds

May 28, 2001

Amazon forest birds are particularly sensitive to habitat fragmentation -- even patches as big as 250 acres are missing many species -- but no one knows why. New research offers a clue: birds in fragments have slower-growing feathers. This suggests that they are more stressed, which could decrease survival and reproduction.

"There might be physiological consequences for birds that live in fragments," says Jeff Stratford of Auburn University in Auburn, Alabama, who did this work with Philip Stouffer of Southeastern Louisiana University in Hammond, Louisiana. This work is in the June issue of Conservation Biology.

This the first evidence that fragmentation may have direct physiological effects.

Stratford and Stouffer compared feathers from two common bird species (the white-crowned manakin and the wedge-billed woodcreeper) that were captured in either forest fragments or continuous forest near Manaus, Brazil. To determine how fast the feathers had grown, the researchers measured the daily growth bars. Healthier birds presumably have feathers with wider growth bars.

The researchers found that feathers from birds captured in forest fragments had grown slower: for instance, feathers from birds in 2.5-acre fragments grew 10% slower than those from birds in continuous forest.

Why do birds in fragments have slower growing feathers? Stratford and Stouffer ruled out the obvious possibility of insufficient food. The manakin's diet includes fruit and the woodcreeper eats insects living on tree trunks and branches, and fragmentation does not reduce either type of food.

In fact, fragmentation may not even affect feather growth directly. Rather, less robust birds may be more likely to end up in undesirable habitats like fragments. This is supported by the finding that manakins were rarely recaptured in fragments, implying that they had grown their feathers in continuous forest. "We suggest that these birds are social subordinates that are wandering about the landscape," says Stratford.

Birds in fragmented habitats elsewhere may be even more stressed because the fragmentation in this study was relatively mild. For instance, the forest fragments were separated by pasture and regenerating forest rather than by parking lots and houses. "Even though things look bad, this is a 'best case scenario'," says Stratford.
-end-
For more information contact:
Philip Stouffer (504-549-2191, stouffer@selu.edu)

For faxes of papers, contact Robin Meadows robin@nasw.org

For more information about the Society for Conservation Biology: http://conbio.net/scb/

Society for Conservation Biology

Related Birds Articles from Brightsurf:

In a warming climate, can birds take the heat?
We don't know precisely how hot things will get as climate change marches on, but animals in the tropics may not fare as well as their temperate relatives.

Dull-colored birds don't see the world like colorful birds do
Bengalese finches -- also called the Society finch -- are a species of brown, black and white birds that don't rely on colorful signals when choosing a mate.

Some dinosaurs could fly before they were birds
New research using the most comprehensive study of feathered dinosaurs and early birds has revised the evolutionary relationships of dinosaurs at the origin of birds.

If it's big enough and leafy enough the birds will come
A new study from the Cornell Lab of Ornithology highlights specific features of urban green spaces that support the greatest diversity of bird species.

How do birds understand 'foreign' calls?
New research from Kyoto University show that the coal tit (Periparus ater) can eavesdrop and react to the predatory warning calls of the Japanese tit (Parus minor) and evokes a visual image of the predator in their mind

Microelectronics for birds
Ornithologists and physicists from St Petersburg University have conducted an interdisciplinary study together with colleagues from Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences and the Biological Station Rybachy of the Zoological Institute of the Russian Academy of Sciences.

Birds of a feather better not together
A new study of North American birds from Washington University in St.

Not-so-dirty birds? Not enough evidence to link wild birds to food-borne illness
Despite the perception that wild birds in farm fields can cause food-borne illness, a WSU study has found little evidence linking birds to E. coli, Salmonella and Campylobacter outbreaks.

Birds are shrinking as the climate warms
After 40 years of collecting birds that ran into Chicago buildings, scientists have been able to show that the birds have been shrinking as the climate's warmed up.

Diving birds follow each other when fishing
Diving seabirds watch each other to work out when to dive, new research shows.

Read More: Birds News and Birds Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.