Table 1 summarizes characteristics of the data sets used by to make comparisons (Bower (2009). To perform a third comparison of marine bird observations over time, Bower (2009) analyzed annual Christmas Bird Count (CBC) data from 11 count circles north of Puget Sound (07). Results of the WWU/MESA comparison of data were largely consistent with the MESA/PSAMP comparison (Nysewander et al. The WWU/MESA comparison study replicated land-based and ferry-based transect portions of the MESA surveys over two winters (05). In acknowledgment of these concerns and the multiple problems associated with comparing results across disparate survey methodologies, the Western Washington University (WWU) or WWU/MESA comparison study was initiated (Bower 2009). Wahl 2002) sparked concern over declines in marine birds in Puget Sound. Furthermore, the PSAMP used aerial surveys, but the potential bias associated with avoidance of aircraft by birds has not been evaluated. Although methodologies used in MESA and PSAMP surveys were relatively comparable, differences did exist, for example in the locations and habitat types surveyed by the aerial methods, and in the proportion of the MESA baseline data that was from aerial, land-based and ferry-based surveys. For some species, such as the western grebe ( Aechmophorus occidentalis) and long-tailed duck ( Clangula hyemalis), declines were as high as 95% and 91%, respectively. Results of this analysis revealed significant declines in 13 of the 20 species or species groups studied, including declines in at least one species from each marine bird family found in northwestern Washington. (2005) evaluated long-term changes in abundance in several species of marine birds by comparing the PSAMP results from 54 aerial transects with results from nearly identical MESA transects. 2010 with permission from Washington Department of Fish and Wildlife) Map of PSAMP subregions (Reprinted from Evenson et al. Aircraft-based observers record all bird species seen below the high tide line, but monitoring goals and data summaries emphasize certain alcid, diving duck, loon, and grebe species.įigure 1. The annual surveys consist of aerial transects covering nearshore habitat and offshore habitat/open waters throughout Puget Sound and the southern shore of the Strait of Juan de Fuca (Figure 1). Notably, the study included only the southernmost portion of the Strait of Georgia and not Puget Sound itself.īeginning in 1992, the Puget Sound Ambient Monitoring Program (PSAMP) began collecting observations of marine birds in the non-breeding season this currently is the only source of continuous multi-species monitoring of marine birds in Puget Sound. It included aerial, land-based, and ferry-based transect surveys north of Admiralty Inlet, within portions of the Straits of Juan de Fuca and Georgia, and the Canadian Gulf Islands. The MESA study was a large-scale survey jointly funded by the Department of Commerce (DOC) and the Environmental Protection Agency (EPA) as a response to oil spill threats in the Strait of Juan de Fuca. Since the 1970s, the most comprehensive census of marine birds in northern Puget Sound was conducted as part of the Marine Ecosystems Analysis (MESA) program of 1978-1979 (Wahl 1981). Information pertaining to marine bird distribution and abundance prior to the 1970s resides primarily in anecdotal accounts (Rathbun 1915, Jewett 1953) and systematic surveys held during Christmas Bird Counts (CBCs), which became consistent and widespread in the 1960s. Studies have focused primarily on abundance and distribution, habitat utilization, foraging behavior, and contamination levels. More than 70 bird species regularly utilize Puget Sound during some or all stages of their life histories (Gaydos and Pearson 2011), but only a portion of these are actively being investigated. Haydel’s Game Calls is family owned and operated and is nationally recognized as a leader in the manufacture of the finest quality game calls.Puget Sound is important for nesting, wintering, and migration of numerous bird species associated with the marine environment. It features a removable plug in the exhaust barrel for added volume. While traditional Mallard Calls have often times been used in a crutch this duck call has been specifically designed for the purpose of dedicated diver duck hunters. The Diver Duck Call creates the “Brrrrr” sound that Redheads, Bluebills, Scaup, Canvasbacks and others use to communicate. The DC-14 Diver Duck Call was specifically designed for dedicated diver hunters. HAYDEL'S Game calls Diver Duck Call (DC-14) Product Info for HAYDELS Diver Duck Call DC-14 Removable plug in the exhaust barrel for volume control.Produces the communication call used by Redheads, Bluebills, Scaup, Canvasbacks, and other divers.Features of HAYDELS Diver Duck Call DC-14
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |