 
Snowy
Plover Distribution, Abundance and Reproductive Success: 2006 Research
Progress Report
PDF Format - [813K]
Related links:
Snowy Plover Population Monitoring, Research, and Management Actions: 2008 Nesting Season Research Progress Report
Snowy Plover Population Monitoring, Research, and Management Actions: 2007 Nesting Season Research Progress Report
ACKNOWLEDGMENTS
Max Zahn and Warren Michaelis from WDFW conducted adult population surveys
and volunteers Larry Lock, Alan Knue, Craig Zora, Martha Jensen, and John
Grettenberger conducted surveys of previously occupied but currently unoccupied
sites. The Shoalwater Tribe and Steve Spencer in particular provided access
to tribal land for plover surveys and assisted with plover surveys. Washington
State Parks staff including Lisa Lantz, Julie Tennis, Jim Schmidt, Steve
Wood, Evan Roberts, and Ed Girard assisted with land management issues
including enforcement, signing and fencing. Martha Jensen assisted with
surveys, funding, and has been extremely helpful in our monitoring and
management actions. Wan-Ying Chang and Gail Olsen provided excellent statistical
advice. Dave Lauten and Kathy Castelein provided invaluable advice on several
aspects of this work. Stephen J. Davies gave us permission to use his Snowy
Plover pictures. This Work was funded by a grant from U.S. Fish and Wildlife
Service. Thank you all!!! |
Snowy
Plover Distribution, Abundance and Reproductive Success:
2006 Research
Progress Report
Scott
F. Pearson and Cyndie Sundstrom, Washington Department of Fish and Wildlife
Kirsten
Brennan and Marie Fernandez, U.S. Fish and Wildlife Service
January
2007
Overview
During the 2006 Western Snowy Plover (Charadrius
alexandrinus nivosus) nesting season, we monitored breeding phenology, nesting success, fledging success and the number of nesting adult plovers in Washington. In addition, we used occupancy models to determine the number of site visits needed to have a high probability of detecting plovers should they be present. Finally, we examine detectability issues and sources of bias associated with our adult population estimates and make recommendations for future surveys and research. A quick summary of some of our 2006 results: Breeding Phenology
- Clutches were initiated between 18 April and 8 July. The last chick known to fledge, fledged around 5 September.
Breeding Range
- Snowy plovers nested on Leadbetter, Midway Beach, Graveyard Spit, and the Damon Point area.
- The Graveyard Spit (Shoalwater Indian Reservation) nesting site was discovered this season.
- Our occupancy models indicate a high probability of determining site occupancy with three or four visits to a site by experienced observers between early to mid-May and the end of the first week of July – the period of greatest plover nesting activity.
Number of Breeding Adults
- Washington breeding adult population = 70 (95% Confidence interval = 56-84). Nearly all of the breeding adults were found on Leadbetter Point and Midway Beach.
- Errors associated with double counting and detectability were addressed.
Nesting Success
- Nest success in Washington was 25% and the primary sources of nest failure were predation (primarily by crows and ravens) and nest buried by drifting sand.
Fledging Success
- The average number of young fledged per adult male on several sites in Washington was between 0.76 and 1.45 with a mean of 1.02. It is important to remember that the Leadbetter Point plovers (nearly half the population in Washington) were not included in this estimate and, because we saw very few chicks or juvenile birds at this site, we suspect that fledging success at Leadbetter was lower than at the other Washington sites. As a result, we believe that this estimate is an overly optimistic estimate of fledging success in Washington for the year and also suspect that the Washington population is currently not self-sustaining.
Captive Rearing
- One abandoned chick was collected and taken to the Oregon Coast Aquarium in Newport. The chick was not releasable because of a problem with one of its wings (unable to fly) and it remains in the Snowy Plover exhibit at the aquarium.
- Six eggs were collected from three failed nests (buried with sand) and placed in an incubator to attempt hatching. Three of the six eggs hatched and all chicks were transported to the Oregon Coast Aquarium for captive rearing and all three were released at Leadbetter.
Management Actions
- Numerous management actions benefited plovers including beach access restrictions, enforcement and education activities, habitat restoration area enlargement, and nest exclosures were placed around some plover nests.
Monitoring and Research Recommendations
- Continue testing methods for determining site occupancy and for estimating adult population size.
- Determine fledging success rates for Leadbetter.
- Examine the effectiveness of habitat restoration areas.
- Assess the impact of human disturbance on nesting plovers and on fledging success.
- Examine methods for creating a self-sustaining population.
|
