|
Résumé :
|
Capturing shorebirds during the non-breeding season can be challenging because they are usually scattered over wide-open intertidal areas while foraging and are sensitive to human disturbance at roosts where they gather during high tide in large vigilant flocks. Several techniques are available for capturing shorebirds, but, for a study of stopover ecology, we needed a method that would allow us to capture Dunlins (Calidris alpina) on a regular basis at high-tide roosts during the day (ruling out mist-nets), did not require the use of gun-powder (ruling out cannon-nets), and that would deploy a net faster than clap nets, whoosh nets, and wilsternets. Therefore, we developed a new method to capture shorebirds where a crossbow is used to pull a mist-net over flocks of roosting birds. We tested this technique in four habitats (saltpans, salt marshes, beaches, and mudflats) in the Tagus estuary, Portugal, and captured over 380 birds representing eight different species. Advantages of this technique compared to other methods (e.g., mist-nets, clap- and whoosh nets, and cannon-nets) include (1) portability, (2) ease of set up, (3) minimal disturbance of birds near the capture area, and (4) no explosive materials are needed. Our results suggest that crossbow-netting is a safe and useful capture technique, especially for studies requiring the capture of small numbers of birds on a regular basis.
|