Acadia's Phil Taylor Collaborates with UMaine researchers on bird research

The Gulf of Maine is a major migration route for many species of birds heading south for the winter and north for the summer. The newly established Northeast Regional Migration Monitoring Network, a group of researchers that includes UMaine biologist Rebecca Holberton and other UMaine scientists, has spent the last two years trying to determine where and when migrating species fly over the Gulf’s complex network of islands and coastal areas.

The Network, which also includes biologists from the U.S. Fish & Wildlife Service Maine Coastal Islands National Wildlife Refuge, the National Park Service, and Acadia University in Nova Scotia, has taken a groundbreaking comprehensive approach to studying the region’s migrating birds, many of whom face threats from climate change and habitat loss.

“The scale at which Network members are combining their expertise to document where and when birds move through the area is unprecedented,” said Holberton of the Laboratory of Avian Biology at UMaine’s School of Biology and Ecology. “There has never been such a combination of techniques and technology applied to bird migration in this region before, and we are beginning to make some exciting discoveries.”

According to a recent U.S. Fish & Wildlife Service press release, a banding program, headed up by UMaine doctoral student Adrienne Leppold along with USFWS biologists and the National Audubon Society, revealed last fall that as many as a half million or more songbirds fly over Maine’s island and coastal areas just in the mid-coast region alone.  Leppold’s spring migration studies at Metinic Island this year showed that migrating songbirds also use these same areas as they return north.

The majority of terrestrial bird species moving through the Gulf of Maine region breed in the boreal forest, taiga, and tundra – regions that have been and will continue to be impacted by climate change and habitat destruction. In order for Network researchers to gain an accurate picture of migration patterns and the birds’ relationships with the region’s habitats, research integrates the broad landscape scale with the individual level.

Observing migrating birds during daytime can be done through systematic visual surveys.  Most migrants, however, make their way under the relative safety of the night when the winds tend to be calmer and the risk of predation is low. This makes it challenging for researchers to document the kinds and numbers of birds on the move, and when and where they pass through the region.

One of the methods being used by the Network is passive acoustic surveys, in which sensitive microphones pick up species-specific calls that, when recorded at different locations, provide information about the timing and flight paths of these birds. Passive acoustic surveys complement information from marine surveillance radar, which documents the density, flight altitude and direction of birds migrating overhead. Holberton has established the UMaine Avian Acoustic Analysis Lab in which graduate and undergraduate students are learning how to analyze the acoustic data and identify the sounds of thousands of bird flight calls being recorded during the migration season.

At least five teams operated banding stations this fall. Capturing birds at banding sites can reveal not only which species migrate through the area, but provide an opportunity to assess the energetic condition and overall health of the birds. This fall, banders encountered several unexpected birds in the region, including two MacGillivray’s Warblers, a western species that has been documented only twice before in Maine.

Stable isotope markers incorporated in small feather samples taken from the birds in autumn are being analyzed by collaborators with the Canadian Wildlife Service-Environment Canada to determine where individuals have bred or where they were born.  Samples taken in the spring can provide information about where birds spent the winter. This method does not require that a bird has been previously captured and banded with an individually numbered leg band. Further, it provides important information about how connected the Gulf of Maine region is to the birds’ breeding grounds to the north and wintering areas far to the south.

Migratory decisions at the scale of the individual bird – a challenge because the songbirds’ small size makes them difficult to track through more traditional satellite telemetry methods used with larger species – are also being closely examined. Acadia University’s Phil Taylor and his graduate student, Brad Woodworth, are deploying tiny transmitters developed by the Canadian company Lotek Wireless on small songbirds in southwestern Nova Scotia. Birds carrying these transmitters can be detected by an array of receivers set up along the coast of Nova Scotia and Maine telling the researchers the flight path an individual bird has taken as it moves through the region.  This is the first time that the flight and stopover movements and rate of migration of free-flying individual songbirds have been documented in the Gulf of Maine.

“The Migration Monitoring Network is revealing exciting information about the movement of birds in our region,” Holberton said. “Many of these populations are declining at an alarming rate. Clearly, the Gulf of Maine encompasses critical flyways that provide important resources for millions of birds. Given the growing pressure for development of coastal areas for near-shore and terrestrial-based wind development and other activities in the region, we need to have a better understanding of bird migration here in order to direct efforts into responsible resource management on a large regional scale.”

 

Source: http://umaine.edu/news/blog/2010/10/15/umaine-among-leaders-of-groundbreaking-research-into-bird-migration-in-gulf-of-maine/

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