Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

The Ability of Oystercatchers Haematopus ostralegus to Compensate for Lost Feeding Time: Field Studies on Individually Marked Birds

A. J. Urfi, J. D. Goss-Custard and S. E. A. Lev. Dit Durell
Journal of Applied Ecology
Vol. 33, No. 4 (Aug., 1996), pp. 873-883
DOI: 10.2307/2404958
Stable URL: http://www.jstor.org/stable/2404958
Page Count: 11
  • Read Online (Free)
  • Download ($18.00)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
The Ability of Oystercatchers Haematopus ostralegus to Compensate for Lost Feeding Time: Field Studies on Individually Marked Birds
Preview not available

Abstract

1. Wintering shorebirds are often disturbed by people and raptorial predators, causing them to loose feeding time and making it more difficult for them to meet their high energy demands. Previous work on captive oystercatchers, Haematopus ostralegus, suggests that they may be able to compensate for the lost time by increasing the rate at which they feed, but it is not known whether free-living oystercatchers can do so. This paper tests this possibility on five individually marked wild oystercatchers feeding on mussels Mytilus edulis. 2. Each marked bird was monitored continuously throughout tidal exposure periods between August 1993 and February 1994 on days during which disturbance either did or did not occur. The disturbance was either natural (raptors) or human, this either arising from shellfishermen or being experimentally induced. 3. A multiple regression model was built for each bird using data only from undisturbed days to establish trends in intake rate associated with environmental factors, such as competitor density, the season and state of the tide. These were used to predict the intake rate that would have been expected to occur, had the disturbance not taken place. These expected 'undisturbed rates' were then compared to the actual rates after a disturbance had occurred. 4. The 'disturbed' and 'undisturbed' rates were not significantly different, either in the immediate post-disturbance period or over the remainder of the exposure period. Plots of cumulative biomass consumption showed that individual birds on disturbed days took longer to achieve a given consumption than on undisturbed days. Contrary to the hypothesis, there is no evidence that these birds increased their rate of feeding to compensate for lost feeding time. Instead, they extended their feeding time by remaining longer on the mussel bed. When time losses due to disturbance are rather short (30-60 min), the results suggest that there is some 'slack' in the system which oystercatchers are able to exploit to compensate for time lost through disturbance. 5. Studies on three sites with differing frequency of disturbance by people suggest that the birds are able to habituate to the frequent presence of people and to reduce the distance at which they take flight, thus reducing the amount of time lost to disturbance in the first place.

Page Thumbnails

  • Thumbnail: Page 
873
    873
  • Thumbnail: Page 
874
    874
  • Thumbnail: Page 
875
    875
  • Thumbnail: Page 
876
    876
  • Thumbnail: Page 
877
    877
  • Thumbnail: Page 
878
    878
  • Thumbnail: Page 
879
    879
  • Thumbnail: Page 
880
    880
  • Thumbnail: Page 
881
    881
  • Thumbnail: Page 
882
    882
  • Thumbnail: Page 
883
    883