Influence of call broadcast timing within point counts and survey duration on detection probability of marsh breeding birds
| Autor: | C. Myles Falconer, Annie Bracey, Erin E. Gnass Giese, Christopher J. Norment, Douglas C. Tozer, Gerald J. Niemi, Robert W. Howe, Thomas M. Gehring |
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| Rok vydání: | 2017 |
| Předmět: |
s Marsh Monitoring Program
0106 biological sciences Marsh Standardized North American Marsh Bird Monitoring Protocol Discount points 01 natural sciences SB1-1110 s Great Lakes Coastal Wetland Monitoring Program Central Michigan University’ Bird Studies Canada’ audio lures GE1-350 QK900-989 Duration (project management) Plant ecology Ecology Evolution Behavior and Systematics Nature and Landscape Conservation geography.geographical_feature_category Ecology 010604 marine biology & hydrobiology Plant culture Environmental sciences 010601 ecology Geography call broadcasts Animal Science and Zoology |
| Zdroj: | Avian Conservation and Ecology, Vol 12, Iss 2, p 8 (2017) |
| ISSN: | 1712-6568 |
| Popis: | The Standardized North American Marsh Bird Monitoring Protocol recommends point counts consisting of a 5-min passive observation period, meant to be free of broadcast bias, followed by call broadcasts to entice elusive species to reveal their presence. Prior to this protocol, some monitoring programs used point counts with broadcasts during the first 5 min of 10-min counts, and have since used 15-min counts with an initial 5-min passive period (P1) followed by 5 min of broadcasts (B) and a second 5-min passive period (P2) to ensure consistency across years and programs. Influence of timing of broadcasts within point counts and point count duration, however, have rarely been assessed. Using data from 23,973 broadcast-assisted 15-min point counts conducted throughout the Great Lakes-St. Lawrence region between 2008 and 2016 by Bird Studies Canada's Marsh Monitoring Program and Central Michigan University's Great Lakes Coastal Wetland Monitoring Program, we estimated detection probabilities of individuals for 14 marsh breeding bird species during P1B compared to BP2, P1 compared to P2, and P1B compared to P1BP2. For six broadcast species and American Bittern (Botaurus lentiginosus), we found no significant difference in detection during P1B compared to BP2, and no significant difference in four of the same seven species during P1 compared to P2. We observed small but significant differences in detection for 7 of 14 species during P1B compared to P1BP2. We conclude that differences in timing of broadcasts causes no bias based on counts from entire 10-minute surveys, although P1B should be favored over BP2 because the same amount of effort in P1B avoids broadcast bias in all broadcast species, and 10-min surveys are superior to 15-min surveys because modest gains in detection of some species does not warrant the additional effort. We recommend point counts consisting of 5 min of passive observation followed by broadcasts, consistent with the standardized marsh bird protocol, for surveying marsh breeding birds. |
| Databáze: | OpenAIRE |
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