Featured Research

from universities, journals, and other organizations

Trends In Bird Observations Reveal Species' Changing Fortunes

Date:
April 10, 2007
Source:
American Institute of Biological Sciences
Summary:
Some 40 years of observations catalogued in the North American Breeding Bird Survey show strikingly different changes in the circumstances of birds preferring various habitats and with various migratory habits.

Data gathered over decades by the thousands of volunteers who participate in the North American Breeding Bird Survey have yielded a vivid portrait of trends in the abundance of birds in eastern North America. In an article in the April 2007 issue of BioScience, Ivan Valiela, of the Boston University Marine Program, and Paulina Martinetto, at Argentina's Universidad Nacional de Mar del Plata, describe how they analyzed data from 40 years of observations made by volunteers who each year drive set routes. Valiela and Martinetto classified the observations by species' habitat preference and migratory habit.

Although the total number of birds recorded as nesting in the eastern and central United States has steadily decreased, the losses were heavily concentrated among species that either resided or migrated within the United States and Canada. The numbers of those that migrated farther south after the nesting season mostly did not decline, and some Neotropical migrants increased in abundance. The trends varied, however, between birds preferring different habitat.

The North American Breeding Bird Survey is susceptible to a variety of possible biases. For example, new road construction since the 1960s may have some bearing on the number of birds that volunteers notice. Yet the differences in how the number of observations changed over time for birds preferring different habitats add up to a strong case for further research.

The researchers found that decreases were especially common among birds preferring open, edge, and wetland habitat, a fact they tentatively ascribe to the spread of industrial, suburban, and other human-affected land cover in North America--loosely, "urban sprawl." Forest-loving species, in contrast, often increased in abundance, an observation that finds a likely explanation in the expansion of northern forests during much of the 20th century.

The increases among forest-loving birds were most pronounced, however, among species that migrate south of the United States--a surprise, given the well-known loss of Neotropical forests. Likewise, numbers of open-habitat birds that migrate south for the northern winter did not, by and large, increase as a result of the growing expanse of pasture in the Neotropics. A possibly related surprise is the relative lack of declines among wetland-loving birds that migrate south of the United States.

All told, the patterns prompt Valiela and Martinetto to suggest that alterations in the northern part of the ranges of migrant birds dominate over the effects of changes further south, an effect that is so far unexplained.


Story Source:

The above story is based on materials provided by American Institute of Biological Sciences. Note: Materials may be edited for content and length.


Cite This Page:

American Institute of Biological Sciences. "Trends In Bird Observations Reveal Species' Changing Fortunes." ScienceDaily. ScienceDaily, 10 April 2007. <www.sciencedaily.com/releases/2007/04/070402101742.htm>.
American Institute of Biological Sciences. (2007, April 10). Trends In Bird Observations Reveal Species' Changing Fortunes. ScienceDaily. Retrieved September 16, 2014 from www.sciencedaily.com/releases/2007/04/070402101742.htm
American Institute of Biological Sciences. "Trends In Bird Observations Reveal Species' Changing Fortunes." ScienceDaily. www.sciencedaily.com/releases/2007/04/070402101742.htm (accessed September 16, 2014).

Share This



More Plants & Animals News

Tuesday, September 16, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Some Tobacco Farmers Thrive Amid Challenges

Some Tobacco Farmers Thrive Amid Challenges

AP (Sep. 16, 2014) The South's tobacco country is surviving, and even thriving in some cases, as demand overseas keeps growers in the fields of one of America's oldest cash crops. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

AFP (Sep. 16, 2014) Scientists say a female colossal squid weighing an estimated 350 kilograms (770 lbs) and thought to be only the second intact specimen ever found was carrying eggs when discovered in the Antarctic. Duration: 00:47 Video provided by AFP
Powered by NewsLook.com
Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Conservationists Face Uphill PR Battle With New Shark Rules

Conservationists Face Uphill PR Battle With New Shark Rules

Newsy (Sep. 14, 2014) New conservation measures for shark fishing face an uphill PR battle in the fight to slow shark extinction. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

      Technology News



      Save/Print:
      Share:

      Free Subscriptions


      Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

      Get Social & Mobile


      Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

      Have Feedback?


      Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
      Mobile: iPhone Android Web
      Follow: Facebook Twitter Google+
      Subscribe: RSS Feeds Email Newsletters
      Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins