Chapter 30 



Marbled Murrelet Populations of Washington 



Marine Habitat Preferences and Variability of Occurrence 



Steven M. Speich 



Terrence R. Wahl 2 



Abstract: Marbled Murrelets occur in Puget Sound marine habitats 

 in relatively low numbers. The rates of occurrence of murrelets on 

 censuses within marine habitats is generally low. Further analysis 

 is required to determine if low occurrence rates are a general 

 function of the movement of birds, or their consistent occurrence 

 on particular censuses and not on others. Qualitative data indicate 

 that Marbled Murrelet abundance in Puget Sound is now lower than 

 earlier this century. Such long-term information is unavailable for 

 Marbled Murrelets along the Pacific Ocean coast of Washington. 

 Census data from nearshore waters of the Pacific Ocean off Grays 

 Harbor indicate that Marbled Murrelet abundance is reduced there 

 since 1989 and especially in 1993. This pattern is also reflected in 

 several other more oceanic species suggesting basic and wide- 

 spread changes in marine carrying capacity. 



Early reports on the birds of Washington (Dawson and 

 Bowles 1909, Jewett and others 1953) consisted primarily of 

 interesting general accounts, whereas several recently published 

 reports have focused specifically on marine birds in Washington 

 (Briggs and others 1992; Cody 1973; Grover and Olla 1983; 

 Manuwal and Campbell 1979; Manuwal and others 1979; 

 Paine and others 1990; Speich and Wahl 1989; Wahl 1984; 

 Wahl and Speich 1984; Wahl and Speich, in press; Wahl and 

 others 1981; Wilson 1991). Despite these reported activities 

 of researchers, including ourselves, little has been written of 

 the habitat preferences of marine birds, including Marbled 

 Murrelets, in Washington. Lately, a few general descriptions 

 and quantifications of the abundance of marine birds based 

 on marine habitats have appeared. While only the reports of 

 Wahl and others (1981) and Long (1983) are pertinent to 

 Puget Sound, and of Wahl (1984,,, Speich and others (1987), 

 and Briggs and others (1992) to the Pacific Ocean coast, 

 they only marginally included the Marbled Murrelet. The 

 same paucity of information pertains to the foods of marine 

 birds in Washington marine areas, with the exception of a 

 few species specific studies (e.g., Rhinoceros Auklet 

 [Cerorhinca monocerata] [Wikon and Manuwal 1986]). Little 

 has been written that specifically deals with Marbled Murrelets 

 in Washington marine waters (Speich and others 1992; 

 Thoresen 1989; Varoujean and Williams, this volume). 



Marbled Murrelets are found throughout the Puget Sound 

 region, although their distribution varies spatially and 

 temporally (Speich and others 1992; Wahl and others 1981; 

 Wahl and Speich 1983, 1984). Speich and others (1992) 



1 Research Ecologist, Dames & Moore, Inc., 1 790 E. River Road, Suite 

 E-300, Tucson, Arizona 85718 



2 Naturalist, 3041 Eldridge, Bellingham, Washington 98225 



attempted to establish the size of populations in each of the 

 major marine areas of Washington, to determine if a seasonal 

 change in numbers occurred, and to evaluate historical marine 

 evidence for changes in the numbers of breeding birds. The 

 results were a breeding population estimated at near 5,000 

 Marbled Murrelets, evidence of an influx of birds into at 

 least Puget Sound during the winter, and an indirect conclusion 

 that the breeding population in Puget Sound had declined 

 from early periods, although the magnitude of the change is 

 unknown and cannot be quantified. Our impression is that 

 murrelets are variable in their occurrence, moving from one 

 area to another, often in short time periods, although birds 

 are often found in specific areas. 



In this paper we quantify and discuss the seasonal 

 geographic and marine habitat distribution, abundance and 

 variability of Marbled Murrelets in Washington marine waters. 

 Changes in abundance over the past 23 years of censusing 

 continental shelf waters near Grays Harbor are explored. 



Methods 



The inland marine areas of Washington, better known as 

 Puget Sound, are a complex of bays and passages, supporting 

 a large variety of marine habitats and associated organisms 

 (Long 1983, Simenstad and others 1979). They are connected 

 by larger deep water areas such as the Strait of Juan de Fuca, 

 Admiralty Inlet, Haro Strait, Rosario Strait and Georgia Strait, 

 all distinct habitats. During the 1978 and 1979 National 

 Oceanic and Atmospheric Administration (NOAA) Marine 

 Ecosystem Analysis Program (MESA), marine bird surveys 

 of northern Puget Sound (Wahl and others 1981) censuses 

 were established and conducted. These quantified distribution 

 and abundance of the marine birds found in all the major 

 marine habitat types and geographic areas of northern Puget 

 Sound. During the MESA program, northern Puget Sound 

 was divided into 1 1 major regions and 72 subregions, largely 

 based upon marine and terrestrial geography and water depth. 

 Each subregion, and certainly each region, contained one or 

 more distinct marine habitat types, based on water depth, 

 marine substrate type, slope and, in part, geography. Each 

 region, subregion and habitat type was overlain with one or 

 more distinct marine census transects. These transects were 

 fixed in location and were censused by one or more 

 standardized census methods. Census methods included small 

 aircraft, small boats, Washington State Ferries, and fixed 

 locations at points, about bays, and along beaches. Census 

 data were lumped by location, marine habitat, subregion and 

 region, and time period, as appropriate. In the habitat analysis 

 for this paper, censuses were combined by habitat type and 



USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. 



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