The importance of survey timing in monitoring breeding seabird numbers
Waterbirds
By: C.M. Johnson and W.B. Krohn
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Abstract
We conducted weekly aerial surveys of islands along the central Maine coast from April-June of 1993-1997 and used aerial photographs to determine peak nest count dates for Double-crested Cormorants (Phalacrocorax auritus), Herring Gulls (Larus argentatus) and Great Black-Backed Gulls (Larus marinus). These data also were used to determine the potential effect of survey timing on the ability to detect long-term trends in the abundance of these species. The number of cormorant nests in the study area peaked in mid-June, while Great Black-backed and Herring gulls peaked in late May and early June, respectively. Peak nesting dates generally were consistent for each island across years, but varied by up to a month between islands during a given year. A 10-year monitoring program using annual surveys conducted between 23 May and 23 June, or biennial surveys conducted from 2-17 June, would have an 80% probability of detecting annual changes of ??5% for all three species in this region. Received 1 November 2000, accepted 4 December 2000.
Suggested Citation
Johnson, C., Krohn, W., 2001, The importance of survey timing in monitoring breeding seabird numbers: Waterbirds, v. 24, no. 1, p. 22-33.
ISSN: 19385390 (online)
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | The importance of survey timing in monitoring breeding seabird numbers |
| Series title | Waterbirds |
| Volume | 24 |
| Issue | 1 |
| Year Published | 2001 |
| Language | English |
| Larger Work Type | Article |
| Larger Work Subtype | Journal Article |
| Larger Work Title | Waterbirds |
| First page | 22 |
| Last page | 33 |