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Home , Barkley Sound, Broken Group, Burrard Inlet, Bute Inlet, Chatham Sound, Checleset Bay

Chapter 29 Marine Distribution, Abundance, and Habitats of Marbled Murrelets in

Alan E. Burger1

Abstract: About 45,000-50,000 Marbled Murrelets (Brachyramphus birds) are extrapolations from relatively few data from 1972 marmoratus) breed in British Columbia, with some birds found in to 1982, mainly counts in high-density areas and transects most parts of the inshore coastline. A review of at-sea surveys at covering a small portion of coastline (Rodway and others 84 sites revealed major concentrations in summer in six areas. 1992). Between 1985 and 1993 many parts of the British Murrelets tend to leave these breeding areas in winter. Many Columbia coast were censused, usually by shoreline transects, murrelets overwinter in the of Georgia and , but the wintering distribution is poorly known. Aggregations in sum- although methods and dates varied, making comparisons mer were associated with nearshore waters (<1 km from shore in and extrapolation difficult. Much of the 27,000 km of coastline exposed sites, but <3 km in sheltered waters), and tidal rapids and remains uncensused (fig. 1). narrows. Murrelets avoided deep water. Several surveys showed Appendix 1 summarizes censuses for the core of the considerable daily and seasonal variation in densities, sometimes breeding season (1 May through 31 July). Murrelet densities linked with variable prey availability or local water temperatures. are given as birds per linear kilometer of transect. It was Anecdotal evidence suggests significant population declines in the necessary to convert density estimates from other units in , associated with heavy onshore logging in the several cases, and this was done in consultation with the early 1900s. Surveys made between 1979 and 1993 in Barkley and original authors, using charts to determine distances travelled. Clayoquot sounds suggest 20-60 percent declines in densities. These changes are correlated with intensive onshore logging, al- Several authors used strip counts, ranging in width from 300 though El Niño effects are probably also involved. m (e.g., 150 m on either side of the boat) to 1 km, whereas others reported all birds visible from the boat. Relatively few murrelets are likely to be detected at distances >200 m, even in the sheltered inner waters of British Columbia (Burger, British Columbia is second only to in the unpubl. data; Kaiser, pers. comm.), and so these differences population size of Marbled Murrelets and also in complexity in technique, while adding to the variability of the data, were of marine habitats used by these birds. There have been not considered to be a major source of error. many marine studies of this species in British Columbia, beginning with the pioneering work of Sealy in the Queen Gaps in Distribution Charlotte Islands (Sealy 1973b, 1974, 1975a,c), and the There are no obvious gaps in the marine distribution in work of Carter and Sealy in southwestern Island British Columbia, although low densities are associated with (Carter 1984, Carter and Sealy 1984, Sealy and Carter 1984). several large areas (e.g., eastern , eastern Most studies have been short term (one season or less) and , and many of the large mainland ), highly localized. Previous province-wide reviews of marine and this is discussed below. Many areas have not been distributions and habitats relied primarily on data from sight adequately sampled in the breeding season (much of NW record cards, along with a few standardized censuses and NE Vancouver Island, the Strait of Georgia, Strait of (Campbell and others 1990, Rodway 1990, Rodway and Juan de Fuca). others 1992). The sight records are not reanalyzed here. This chapter summarizes data on populations, distribution, habitats, Movements and Seasonal Variations in Density and basic biology of the Marbled Murrelet obtained largely Rodway and others (1992) used an extensive data from boat surveys. base of sight record cards in the Royal British Columbia Museum to demonstrate a post-breeding emigration from Abundance and Distribution areas which support large breeding concentrations on the west coast of Vancouver Island and the Queen Charlotte Regional and Range-Wide Population Densities Islands. Habitat shifts were associated with these changes. Marbled Murrelets have been recorded from most of the Apparent densities (mean numbers of birds per sighting coastal waters of British Columbia (Campbell and others record) were higher in spring and summer than in fall and 1990, Rodway 1990, Rodway and others 1992). Current winter in both exposed inshore waters (1-5 km from shore) estimates of the provincial population (45,000-50,000 breeding and nearshore waters (<1 km of shore) of the Strait of Georgia, but the opposite was true for most fjords. This suggests that murrelets leave the exposed outer coast and more exposed areas of large in late summer and fall 1 Associate Professor (Adjunct), Department of Biology, University of to move into more sheltered waters, including some of the Victoria, Victoria, British Columbia, V8W 2Y2, many large fjords on the mainland.

USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. 295 Burger Chapter 29 Marine Distribution, Abundance, Habitats in British Columbia

Figure 1—The coast of British Columbia showing sites where marine censuses of Marbled Murrelets have been done during the breeding season (May through July).

296 USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. Burger Chapter 29 Marine Distribution, Abundance, Habitats in British Columbia

Shoreline surveys in 1976 and 1977 by Vermeer and There is no evidence of a major move into pelagic others (1983) show similar trends: low densities were found waters in fall or winter (Burger, unpubl. data; Morgan and in October and November in most areas in the Queen others 1991; Vermeer and others 1983, 1989b). Low to Charlotte Islands and nearshore waters of the Strait of moderate densities (0.01 to 1.00 birds per km) were reported Georgia (table 1). Robertson (1974) reported higher densities from only two areas of open water in winter (in central of Marbled Murrelets in protected waters off southwest , between the Queen Charlotte Islands and Banks Vancouver Island in summer (11.19 km2) and found low Island, and over La Perouse Bank off SW Vancouver Island) densities in sheltered during winter (range 0.13-1.17/ (Morgan and others 1991). km2). More recently, high densities were found among Overall, it seems that selected parts of the Strait of Georgia islands on the northern edge of the Strait of Georgia and Puget Sound are the primary wintering areas of murrelets (Harfenist, pers. comm.) and at some inlets off the strait breeding in British Columbia. Small numbers overwinter in (Burns, pers. comm.; Prestash, pers. comm.). most of the coastal waters and more open ocean. Winter Year-round surveys have been made at few sites. Those samples are, however, very inadequate and other important in and adjacent waters show that murrelet wintering areas will undoubtedly be discovered. densities rise in April and decline in late July and August (fig. 2). Some of these birds appear to move into Alberni Habitats Used Canal in winter, but the relatively low densities there cannot account for all the Barkley Sound murrelets. In the Strait of Coarse-Scale Comparisons Georgia, murrelets were more common between Sidney and Marbled Murrelets in British Columbia tend to aggregate Mandarte Island between May and October than in winter, within 500 m of land on exposed shores and within 1-5 km in whereas densities were higher in winter in the sheltered more sheltered waters (Morgan and others 1991; Sealy and fjords of Jervis and Saanich Inlets (fig. 3) and also in Puget Carter 1984; Vermeer and others 1983, 1987). They are Sound in (Speich and others 1992; Speich and relatively rare in more open pelagic water or in the centers of Wahl, this volume). The winter counts might include birds broad straits; consequently these waters were not considered from exposed western and northern parts of British Columbia. in the following analysis.

Table 1—Seasonal changes in densities of Marbled Murrelets recorded during boat surveys in 1976 and 1977 (Vermeer and others 1983)

Density (birds per km) Pre-breeding Breeding Fall Census area (Mar–Apr) (May–Jul) (Oct–Nov)

Strait of Georgia 0.74 – 0.09 Mainland coast 3.38 – 0.43 Jervis 11.02 – 1.46 0.63 – 0.00 Northern strait islands 2.60 – 11.82 Neck Point – Campbell River 0.28 – 0.07 Victoria - Neck Point 0.38 – 0.10 E. Queen Charlotte Islands Houston - Stewart Channel – 2.15 0.10 Skincuttle Inlet – 7.40 0.50 – 4.72 0.10 Logan Inlet - Darwin Sound – 1.78 0.04 - Selwyn Sound – 0.33 0.08 Inlet – 0.46 0.03 East Graham Island coast – – 0.00 N. and W. Queen Charlotte Islands N. Graham Island coast – 0.00 0.02 – 0.00 0.10 Naden Harbour – 0.00 0.04 W. Graham Island coast – 3.00 – W. Graham Island inlets – 0.09 – W. Moresby Island coast – 5.16 – W. Moresby Island inlets – 0.15 –

USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. 297 Burger Chapter 29 Marine Distribution, Abundance, Habitats in British Columbia

Figure 2—Monthly variations in densities of Marbled Murrelets measured in boat surveys in and near Barkley Sound. Data are from shoreline surveys in the Alberni Canal (Vermeer and Morgan 1992), along fixed routes through the Deer Islands in 1979 (Porter 1981) and 1986-1988 (Burger 1994), and along a fixed route between and the islands (Hatler and others 1978). Numbers above columns show numbers of surveys; ND = no data.

Data from the breeding season (generally 1 May through (Long Inlet, Laskeek , Skincuttle Inlet, Poole Inlet and 31 July) in 82 sample areas (some overlapping) show marked Collison Bay); Okeover Inlet in on the variations in density (fig. 4; appendix 1). At a very coarse southern mainland; SE and exposed shores spatial scale (10-100 km), trends include: higher densities off Long Beach, SW Vancouver Island; several parts of on the more sheltered eastern shores of Moresby Island Barkley Sound, SW Vancouver Island; and exposed than in the rest of the Queen Charlotte Islands; higher nearshore water between Barkley Sound and , densities off SW Vancouver Island than NW or NE SW Vancouver Island. This last area supported the highest Vancouver Island; and, surprisingly, higher densities along densities (average >12 birds/km in both 1991 and 1993) for the exposed nearshore coast of western Graham, Moresby, a large stretch of coast (65 km) in British Columbia. and Vancouver Islands than in the inlets off these coasts. The fjords and sheltered waters of the central mainland Major concentrations (>5 birds per linear kilometer on coast supported relatively low summer densities overall average) were found in six : the outer west coast of (average 1.65/km in a 640-km traverse between 15 and 30 Moresby Island (1976 census); several inlets and bays with May 1990; Kaiser and others 1991), but there were some many islands on the sheltered coast of Moresby Island dense patches (Sheep Passage, and Mussel and Kynoch inlets).

298 USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. Burger Chapter 29 Marine Distribution, Abundance, Habitats in British Columbia

Figure 3—Mean monthly densities of Marbled Murrelets in the Strait of Georgia. Data are from fixed shoreline transects in the fjords of (Vermeer 1989), and (Morgan 1989), and from a fixed transect among the southern , between Sidney and Mandarte Island (Clowater, pers. comm.). One survey was done per month, except as otherwise noted. ND = no data.

Stationary counts of Marbled Murrelets at the mouth of • IS: among islands offering relatively sheltered water; Mussel Inlet were high in 1991 (>500 on several days) but • OC: outer coast (for fjords or inlets); lower in 1992 and 1993 (Prestash and others 1992a; Prestash, • IC: inner coast (for fjords or inlets). pers. comm.). These appear to be commuting birds, drawn Each survey was assigned to one or more combinations of from an undetermined area, which are channeled through categories (see appendix 1). narrow fjords en route to feeding areas in more open ocean. Exceptionally high mean densities in May and June (>5 I analyzed coarse-scale habitat use by using the material birds/km) were associated with few habitats: sheltered waters in appendix 1. Habitats were classified as: on the east of the Queen Charlotte Islands, SW Vancouver • E: exposed ocean (facing the open Pacific or exposed Island, and Desolation Sound; and exposed nearshore waters parts of large straits); off SW Vancouver Island (table 2). Exceptionally low summer • S: sheltered water in large strait or sound; densities (<1 bird/km) were found in sheltered nearshore • I: smaller inlet; or waters of NW Vancouver Island and fjords of the southern • F: steep-sided fjord. mainland, southern Strait of Georgia and SW Vancouver Within these categories were subcategories: Island. This analysis is not entirely satisfactory, because • OW: open water (>1 km from shore); some transects covered large areas of diverse habitat, and the • NW: nearshore water (<1 km from shore); habitat classification was not based on detailed field data.

USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. 299 Burger Chapter 29 Marine Distribution, Abundance, Habitats in British Columbia

Figure 4—Mean estimates of the densities of Marbled Murrelets during the breeding season (May through July) from marine surveys in British Columbia. The data are shown as birds per km of transect, which was the most compatible measure among the variable studies (see appendix 1 for details). Most of these data were collected in the 1980s and early 1990s.

Fine-Scale Comparisons Habitats Off NW Vancouver Island, murrelets avoided deep open Several studies reported murrelet habitat use on a finer water in fjords, but in shallower, sheltered bays and exposed spatial scale (0.1-1.0 km). In deep fjords, higher densities nearshore seas densities were higher in open water (5.58/ were associated with estuaries, shallow bays, and waters off km) than in inlets (0.16/km) or channels (0.56/km; Savard beaches (Morgan 1989, Vermeer 1989, Vermeer and Morgan and Lemon 1992). 1992). This might be linked with the habitat supporting prey Sealy and Carter (1984) reviewed the distribution of species such as sand lance (Ammodytes hexapterus), which 9955 sightings of murrelets in a grid census of Barkley and bury themselves in sand for parts of the day (Field 1988). Clayoquot Sounds. Murrelet densities were highest in inshore

300 USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. Burger Chapter 29 Marine Distribution, Abundance, Habitats in British Columbia

Table 2—Mean densities of Marbled Murrelets (birds per km) in marine habitats in British Columbia. Data from appendix 1 (see text for selection criteria). Mean ± s.d. shown, and (in parentheses) range and sample size

Sheltered Exposed nearshore and Region nearshore open / islands Inlets Fjords

N. and W. Queen Charlotte Islands 2.7 ± 2.6 – 1.1 ± 1.2 – (0-5.2; 3) (0-4.0; 12)

E. Queen Charlotte Islands – 5.4 ± 4.4 2.6 ± 0.2 – (0.9-16.0; 11) (2.3-2.9; 6)

Northern and Central Mainland 1.4 ± 1.9 1.1 ± 1.6 2.1 ± 1.8 2.7 ± 1.7 (0-4.2; 5) (0-3.2; 6) (0.6-4.1; 3) (0.4-4.9; 8)

Southern Mainland – 5.11 – 0.63 (-; 1) (-; 1)

Gulf Islands and S. Strait of Georgia – 2.08 – 0.05 (-; 1) (-; 1)

NE. Vancouver Island – 1.2 ± 0.6 – – (0.8-2.2; 5)

NW. Vancouver Island 3.0 0.6 ± 0.6 – – (-; 1) (0.03-1.3; 4)

SW. Vancouver Island 8.5 ± 5.1 4.5 ± 1.3 1.9 ± 1.4 0.7 (4.1-14.2; 5) (2.8-6.0; 6) (0.9-2.9; 2) (-; 1)

areas (12.9 birds/km2), relative to more nearshore channel where d is distance from shore in kilometers. This curve is and fjord habitats (6.3 and 0.2 birds/km2, respectively). Carter plotted in figure 6 for values of d ≥ 100 m. The density for and Sealy (1990) reported lower densities of murrelets in d < 100 m was assumed to be 7 birds/km2 from the data in mid-channel, than in shallower, sheltered nearshore waters figure 5. This model probably applies only to more in Trevor Channel, Barkley Sound. High densities were exposed shores of western Vancouver Island. associated with sheltered, shallow nearshore water and at a A strikingly different distribution pattern emerges from sill at the mouth of the channel, where a thermal front was surveys made in Laskeek Bay, Queen Charlotte Islands, from frequently found (Carter 1984). 1989 through 1993 (see appendix 1 for references). Two I summarized data from Carter’s (1984) grid and transect types of transects were sampled repeatedly: shoreline transects surveys in and near Barkley Sound to show the distribution within 400 m of the surfline and linear transects in open of Marbled Murrelets relative to distance from the shore (fig. water and among islands, up to 3 km from land. The open 5). The distances to shore were estimated from the midpoints water transects often had similar or higher densities than the of each of 12 sample blocks in Trevor Channel and from the nearshore ones, and there was considerable variation within midpoints of each of 16 transect segments in Trevor Channel, and between seasons (fig. 7). The variability in these data Channel, and the open sea off Cape Beale emphasizes the need for caution in interpreting distribution (collectively referred to here as the Cape Beale transects). and census data based on only one or a few seasons. The transect densities were converted from birds/km as given In 1992 the positions of all Marbled Murrelets in open by Carter (1984) to birds/km2 by assuming a 250-m transect water at Laskeek Bay were plotted on a chart to the nearest width on each side of the boat (the same as used in the grid 200 m and, at this fine scale, show the widespread and variable surveys). Murrelets in this area were strongly aggregated distribution of murrelets relative to the nearest land (fig. 6). within 1 km of the shore, with highest densities 100-600 m The pattern in these sheltered waters is quite different from offshore (fig. 5). Similar results were found in grid surveys that of the more exposed outer Barkley Sound area shown by in 1992 and 1993 (fig. 5 inset). Overall, the 1980 data fitted a the logarithmic model (fig. 6). These data clearly illustrate the negative logarithmic curve: problems in estimating total densities for any marine area 2 -1.356 density [birds/km ] = 2.438 d from extrapolations of one or more shoreline transects. The (r2 = 0.735, n = 28, P < 0.001) distribution pattern for open and exposed water is quite

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Figure 5—Densities of Marbled Murrelets in and near southern Barkley Sound between 1 May and 31 July in 1980, 1992, and 1993. The main graph shows densities from grid surveys in Trevor Channel and strip transects near Cape Beale in 1980 (Carter 1984). The inset shows densities from grid surveys in Trevor Channel in 1992-1993 (Burger 1994).

different, and the presence of islands and reefs adds further 1988). Murrelet densities declined rapidly in late July as the complications (see also Sealy 1975c, Sealy and Carter 1984). surface water heated up to near 20o C. Large-scale effects of warm water influxes are described below. Temporal Patterns Using repeated grid surveys in Trevor Channel, Barkley Tidal Patterns and Presence of Rips Sound, Carter and Sealy (1990) showed that local densities The relationship between tides and feeding patterns of of Marbled Murrelets declined, but clumping increased Marbled Murrelets in British Columbia is not consistent. through the day. Consistent high densities in some quadrats Repeated surveys in Barkley Sound (Carter 1984, Carter and direct flights by murrelets into these areas at dawn and Sealy 1990) and Desolation Sound (Kaiser and others indicated that the birds were returning to predictable feeding 1991) reported no significant changes in murrelet densities sites. , a large semi-saline lake adjacent to with tidal state or tidal flow rate. Aggregations of murrelets important forest and marine habitats appears to be used as a at sites with strong tidal flow were reported from Edye staging area for murrelets which leave the forests at dawn Passage and north of Stevens Island, both on the northern and later move to the ocean (Burger 1994). mainland (Fuhr, pers. comm.), Hiekish Narrows (central mainland), and Desolation Sound (Kaiser and others 1991), Effects of Temperature and Salinity Rapids in Jervis Inlet (Vermeer 1989), and Yuculta In fjords and channels in Desolation Sound, Kaiser and Rapids between and the mainland (Prestash, others (1991) found no correlation between murrelet density pers. comm.). Marbled Murrelets were sparse or absent, and sea surface temperature, and a weak positive correlation however, at strong tidal rips at Malibu Rapids (Jervis with salinity (r2 = 0.256, n = 20, P < 0.05). Between 6 June Inlet), and Active Pass (Gulf Islands) where many gulls and 8 August 1990, the murrelets were often concentrated in and other birds were feeding (Vermeer 1989, Vermeer and areas with strong currents, and densities were negatively but others 1987). weakly correlated with sea temperature (r2 = 0.185, n = 15, P < 0.05). Warm water was associated with algal blooms, Abundance Related to Feeding and creating surface turbidity, which might have affected prey Nesting Habitats densities and the birds’ hunting efficiency. The murrelet’s primary prey, sand lance, was usually found in clear water. Effects of Prey Availability These fish are likely to move to deeper water or become There have been no detailed comparisons of murrelet dormant in their burrows in unusually warm water (Field distribution relative to independent measures of prey

302 USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. Burger Chapter 29 Marine Distribution, Abundance, Habitats in British Columbia

Figure 6—Variations of the density of Marbled Murrelets with distance from shore, in exposed (upper) and sheltered (lower) inshore waters in British Columbia. Upper: densities predicted by the logarithmic model derived from Carter’s (1984) counts made in 1980 in Trevor Channel and the Cape Beale area (see fig. 5). Lower: mean densities in 200-m segments of open water surveys made in Laskeek Bay in 1992 (Lawrence, pers. comm.). Error bars show standard deviation.

abundance, such as estimates using echosounders. Carter where murrelets concentrated on euphausiids and sand lance, (1984) explained the influx and aggregations of murrelets in the birds appeared to feed throughout the day (Sealy 1975c). Trevor Channel, Barkley Sound, as a consequence of Availability of sand lance appeared to affect both the spatial aggregations of juvenile herring (Clupea harengus) and sand distribution and the seasonal densities of murrelets in Okeover lance. Murrelet distribution in this area was highly clumped Inlet, Desolation Sound during the breeding season (Kaiser and was associated with features such as gravel or sand and others 1991, Mahon and others 1992). substrates, where sand lance might burrow, or thermal fronts The effects of El Niño and other oceanographic events and small channels, where juvenile herring and other prey on murrelets in British Columbia are poorly known. aggregate (Carter 1984, Carter and Sealy 1990). Carter (1984) Exceptionally warm water persisted off southwestern found that murrelets in Trevor Channel were more likely to Vancouver Island from January through August 1992 and have food in their guts in the morning than in the afternoon again from April through mid-June 1993 (data from H. or at night, and linked this with the availability of sand lance Freeland, in Burger 1994). In Barkley Sound this warm water and juvenile herring in surface waters. Off Langara Island, was associated with an influx of mackerel (Scomber japonicus)

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Figure 7—Densities of Marbled Murrelets in Laskeek Bay, Queen Charlotte Islands, showing seasonal patterns in nearshore surveys (A) and those in open water (B); and inter-year variations in mean densities (C). No open water surveys were made in 1989. Sample sizes show numbers of surveys used to calculate the mean values for the period 26 April through 30 June. Error bars show standard deviations (inverted for 1993 nearshore). Transect widths were 400 m throughout (Lawrence, pers. comm.).

and jack-mackerel (Trachurus symmetricus), which eat prey Abundance and Distribution Relative to Distribution similar to that taken by murrelets, and significantly low densities of Forest Stands of euphausiids and juvenile herring (Hargraves, pers. comm.; There are insufficient data for coarse-scale comparisons Tanasichuk, pers. comm.). Murrelet surveys in the Broken between murrelet densities at sea and rates of detections in Islands showed no effects of these changes in 1992, relative adjacent forests. Murrelet detection frequencies in forest to 1991, but in 1993 many murrelets appeared to leave the surveys on the east coast of Vancouver Island, which has Broken Islands and the Deer Island-Trevor Channel area in been extensively logged, were much lower than on the west June, at least a month before their usual departure (fig. 8). coast (Savard and Lemon in press), and this corresponds to

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Figure 8—Densities of Marbled Murrelets in Barkley Sound, plotted in weekly intervals through the breeding season. One survey was made per week, except where indicated by numbers above the columns. The asterisk indicates a survey with no murrelets seen. Note that the units of density are not the same in all studies. Data from Hatler and others (1978) and Burger (1994).

a general pattern of low densities at sea in summer off the unbroken, and hence more easily censused than along the east coast (appendix 1). highly indented coastline found in most of British Columbia. On a finer scale, Burger (1994) examined murrelet densities Adjacent to this area are some of the largest tracts of old- in 19 segments of coast between and Port San growth forest remaining on southern Vancouver Island, Juan off southwestern Vancouver Island. This 65-km stretch specifically the Nitinat-Tsusiat-Klanawa and Carmanah- of coast has one of the highest known densities of murrelets in Walbran watersheds. The highest at-sea densities in both 1991 British Columbia (appendix 1) and is relatively straight and and 1993 were consistently found in four segments immediately

USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. 305 Burger Chapter 29 Marine Distribution, Abundance, Habitats in British Columbia adjacent to these two tracts of forest, while most of the very June to 26 July 1992 and 86.0 (4-194; six surveys) from 1 low-density areas were adjacent to heavily logged watersheds May to 25 July 1993. These means represent 44 percent and (Burger 1994). The relative importance of marine versus forest 25 percent of the 1980 mean, respectively. The low 1993 habitat in explaining this distribution has not been determined. numbers were partly due to an early departure from this area of murrelets in June, which was associated with persistent Population Changes warm water and possible low prey densities. In 1979, Carter (1984) counted murrelets in a 17.2-km Historical Numbers and Distribution linear transect running through outer Trevor Channel and Rodway (1990) and Rodway and others (1992) reviewed along the open coast to Seabird Rocks. Burger (1994) counted the scanty evidence of long-term population changes in British seabirds along a virtually identical 19.5-km route in 1987, Columbia. There is anecdotal evidence of population declines 1989, 1991, and 1993 and found significantly lower murrelet in the Strait of Georgia. Brooks (1926b) commented on the densities, with the mean values consistently less than 50 scarcity of murrelets on the east coast of Vancouver Island percent of the 1979 value (fig. 9; 1979 data versus pooled in 1925-1926, compared to numbers seen in 1920 and earlier, data 1987-1993: Mann-Whitney test, U7,13 = 79.5, P<0.01). and speculated that disease or crude oil might have been Other censuses suggest that 1979 was not an unusual year in responsible. Pearse (1946) reported a decline in murrelet this area for the study period 1979-1982 (Carter 1984, Sealy numbers in the Comox district, eastern Vancouver Island, and Carter 1984a). These three replicated studies are consistent between 1917 and 1944 and attributed this to the removal of in showing a significant decline in the densities of Marbled coniferous forests. Rodway and others (1992) found no Murrelets in Clayoquot and Barkley sounds. The changes significant trends in numbers of murrelets observed in might be partly due to coarse-scale shifts in distribution, but Christmas Bird Counts made at 22 sites, some extending the Clayoquot Sound surveys covered a large area in which back as far as 1957, but relatively few counts were from distribution shifts of 1-10 km should have been detected. It regularly used wintering areas. is likely that the 1992 and 1993 El Niño conditions caused many murrelets to leave Clayoquot and Barkley Sound Recent Trends temporarily. Support for this hypothesis came in spring 1994 I assessed changes in densities of Marbled Murrelets in when densities of murrelets in Trevor Channel, Barkley the past 15-20 years by comparing surveys made from 1976 Sound, were 2-3 times higher than they had been in 1992 and through 1982 with more recent surveys. Relatively few areas 1993 (Burger, unpubl. data). There is no simple correlation can be compared, and the precise routes and methods of between murrelet numbers and local sea temperatures, some of the earlier surveys could not always be replicated. however, because summer temperatures were also above The paucity of annually repeated surveys makes it difficult normal in early counts in 1979 and 1980 (but not 1982) and to rule out inter-year fluctuations (perhaps related to oceanic in later counts in 1987 and 1989 (data from H. Freeland, in effects) as the cause of some of the changes reported here. Burger 1994). The effects of local ocean temperatures, upwelling events, and El Niño conditions on the distribution Clayoquot Sound and Barkley Sound of Marbled Murrelets and their prey clearly need to be In June 1992 and 1993, Kelson and others (in press; investigated in detail to help explain the apparent declines. Kelson, pers. comm.) repeated the grid census made in One likely cause of decline is the widespread loss of southeastern Clayoquot Sound in June 1982 by Sealy and valley-bottom old-growth forests in the surrounding areas Carter (1984). In each year the entire area (294 km2; (Kelson and others in press, Sealy and Carter 1984). Between Sound excluded) was surveyed once, over periods of several 1954 and 1990, an estimated 75 percent of the ancient rainforest days, by counting all murrelets seen within 250 m of a boat of southern Vancouver Island was logged, including extensive traversing a u-shaped path through each 1-km by 1-km tracts adjacent to Clayoquot and Barkley Sounds (Husband block. The spatial distributions of the birds were broadly and Frampton 1991), and much of this occurred in the past similar in each count, but the total numbers declined from decade. Gill-net fishing also killed appreciable numbers of 4,522 in 1982 to 2,701 (60 percent of the 1982 total) in 1992 murrelets in Barkley Sound (Carter and Sealy 1984), but and 2,622 (58 percent) in 1993. Kelson and others (in press) does not occur here every year (Burger, pers. obs.) and is not attributed the decline to significant reductions in old-growth a factor in Clayoquot Sound (Kelson and others, in press). forests adjacent to Clayoquot Sound. Increased disturbances from sports fishing and recreational Carter (1984) used a similar grid technique in June and boating might have displaced murrelets at a few localities. July 1980 in outer Trevor Channel and the adjacent Deer Islands, one of the areas with consistently high densities in Queen Charlotte Islands Barkley Sound (Carter and Sealy 1984). In 10 morning Nearshore surveys made in May and June in 1977 surveys he recorded a mean of 351.6 birds (on the water and (Vermeer and others 1983) provide comparative data for flying; range 74-518) Repeating these censuses for the some areas in which similar surveys were undertaken in morning periods in 1992 and 1993, Burger (1994) recorded 1990-1992 (table 3). The trends were not consistent; there averages of only 153.0 (range 92-215; four surveys) from 2 were increases in two areas with relatively low densities, but

306 USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. Burger Chapter 29 Marine Distribution, Abundance, Habitats in British Columbia

Figure 9—Mean (±s.d.) densities of Marbled Murrelets on transects of 17.2-19.5 km in Trevor Channel, past Cape Beale and south to Seabird Rocks in June and July of 1979, 1987, 1989, 1991, and 1993 (Burger 1994, Carter 1984). The sample sizes are numbers of transects. Birds seen on the water and flying are shown in shaded and open columns, respectively.

slight declines in two areas in which many murrelets occurred. transits of 7,000 freighters and tankers off British Columbia, The changes were well within the year-to-year variations including at least 1,500 tankers. Each year at least 300 reported for this coast. Considerable logging of old-growth loaded tankers enter the (Shaffer and forests has occurred around and to the north others 1990). Overall, the annual shipments of crude oil of Juan Perez Sound, but the forests adjacent to Skincuttle and refined petroleum products average 26.0 and 15.0 Inlet have not been logged. Oil spills and gill-net fisheries million m3, respectively, in southern British Columbia and do not appear to have been problems for murrelets in any of northern Washington (Shaffer and others 1990). Vessel these areas. The low densities in Massett Inlet shown contrast traffic was estimated to increase by 6-11 percent between with records of flocks of 200 or more in the summers of 1989 and 1991 (Canadian Coast Guard 1991). A probability 1946 and 1947 (Carter 1984), but large flocks were also model predicted that spills exceeding 1,000 barrels are present in May 1990 (Rodway and others 1991). There were expected in southern British Columbia and northern thus no indications of significant population declines in Washington every 2.5 years for crude oil, and every 1.3 these parts of the Queen Charlotte Islands, but the data were years for all petroleum products (Cohen and Aylesworth insufficient to reliably detect any real changes. 1990), and this prediction was close to the actual pattern of spills between 1974 and 1991 (Burger 1992). These studies Threats to Marbled Murrelets at Sea in indicate a high risk from oiling for Marbled Murrelets. This British Columbia is particularly pertinent in inshore areas off southwestern Vancouver Island in summer and southern Strait of Georgia Oil Pollution and Puget Sound in winter, when high murrelet densities There is a moratorium on offshore exploration and coincide with the greatest volumes of tanker traffic and development of oil fields in British Columbia, and this other shipping (Burger 1992). seems likely to continue. Threats to murrelets come from The Nestucca spill in December 1988 killed an estimated catastrophic spills from large vessels as well as chronic 143 Marbled Murrelets off Vancouver Island (Burger 1993a), small-volume spills (Burger 1992, Vermeer and Vermeer which represents about 0.9 percent of the 16,000 birds thought 1975). The Canadian Coast Guard (1991) reported annual to occur off Vancouver Island (Rodway 1990). Marbled

USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. 307 Burger Chapter 29 Marine Distribution, Abundance, Habitats in British Columbia

Table 3—Density estimates (birds per linear km) of Marbled Murrelets at four considered to be most affected by aquaculture in British nearshore sites in the Queen Charlotte Islands surveyed in May–June 1977 and again in spring or summer 1990, 1991 or 1992. See appendix 1 for details Columbia (Rueggeberg and Booth 1989).

Sample area 1977 1990 1991 1992 Conclusions

Massett Inlet 0.0 0.3 – – Proper management of the Marbled Murrelet in British Skidegate Inlet 0.5 1.0 – – Columbia requires an improved estimate of the provincial Juan Perez Sound 4.7 – 3.2 3.6 population and better understanding of its distribution and relative abundance in the breeding and nonbreeding seasons Skincuttle Inlet 7.4 – 3.5 – (Kaiser and others 1992). The census coverage of marine areas has greatly increased over the past decade, but quantitative surveys are still lacking for large tracts of the convoluted 27,000-km coastline (fig. 4). The differences in Murrelet carcasses were rarely found in surveys of beached distribution between exposed and sheltered waters (e.g., fig. birds in southern British Columbia, and were not among the 6) and the variability within and among seasons (e.g. fig. 7 small sample of birds killed by chronic oiling but could and 8) make it very difficult to estimate regional populations easily have been overlooked (Burger 1993b). from single-season shoreline transects. We need to know a lot more about the factors which affect the murrelet’s marine Other Toxic Chemicals distribution, such as prey distribution and effects of tides, High levels of polychlorinated biphenyls (PCBs), dioxins, sea temperature, salinity, and seafloor topography, before and furans have been found in some piscivorous birds in we can plan and interpret census transects and monitor inshore waters of British Columbia, although Marbled population dynamics. Regularly repeated surveys made over Murrelets were not sampled (Elliott and Noble 1993). Levels many years, such as those performed in Laskeek Bay and of these contaminants and of organochlorides appear to be Barkley Sound, will be very valuable in showing both short- declining in water birds sampled in British Columbia (Elliott and long-term patterns. and Noble 1993, Elliott and others 1992). Most of the urgent gaps in our knowledge can be filled by relatively simple, inexpensive studies of fine-scale Gill Nets distribution and foraging ecology if they are carefully planned Little is known about the effects of gill nets on seabirds to collect the most pertinent data. There are also opportunities in British Columbia. In 1988, the gill-net effort totaled 54,770 to tap the expertise of the burgeoning number of birders and net-days, concentrated in summer and fall in inshore areas naturalists who visit remote coastal areas of British Columbia. (Barlow and others 1990). Anecdotal evidence from fishermen The establishment of a long-term data base, meshed with a suggests that Marbled Murrelets are among the bird species Geographic Information System, would facilitate the most often killed. Carter and Sealy (1984) estimated that the accumulation of data from both dedicated and opportunistic bycatch of 200 Marbled Murrelets caught in gill nets in censuses. Other priority problems, such as making a province- Barkley Sound in 1980 represented a loss of 7.8 percent of wide marine census, measuring population demographics, the expected fall population (including loss of fledglings or investigating the effects of gill nets or logging, require caused by deaths of parent birds). There have been no other more dedicated, expensive studies. studies of this problem in British Columbia, but it clearly needs to be examined in detail. Acknowledgments Other Effects of Fishing and Aquaculture Preparation of this chapter was funded by the British Competition with the fishing industry for prey species Columbia Ministries of Forests (Research Branch) and does not appear to be a significant issue for murrelets in Environment, Lands and Parks (Wildlife Branch), and I thank British Columbia. The herring stocks appear to have recovered Brian Nyberg and Don Eastman for their support. I thank after periods of overfishing in the 1960’s and are now strictly Dick Brown, Rick Burns, Tony Gaston, Gary Kaiser, Anne regulated. Sand lance, zooplankton, and other prey species Harfenist, Moira Lemon, Ken Morgan, and Lynne Prestash are not fished in appreciable amounts. Sport fishing continues for valuable comments. Unpublished material was provided to increase, and disturbance from the hundreds of small by Rick Burns, James Clowater, Brian Fuhr (Wildlife Branch), boats, plus occasional bycatch of murrelets on lures is possibly Bob Hanson (Pacific Rim National Park), John Kelson a localized problem. (Conservation International), the Laskeek Bay Conservation Habitat degradation and disturbance at fish and shellfish Society, Andrea Lawrence, Lynne Prestash, Anne Stewart pens can affect Marbled Murrelets, and many aquaculture ( Marine Station), and Anne Harfensit, Gary Kaiser, farms exist or are planned in sheltered inshore waters favored and Moira Lemon of the Canadian Wildlife Service. A special by murrelets (e.g., Clayoquot, Barkley, and Desolation thanks to Andrea Lawrence for assistance in analyzing the sounds). Marbled Murrelets were not among the species Laskeek Bay data and with many other parts of the chapter.

308 USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. Burger Chapter 29 Marine Distribution, Abundance, Habitats in British Columbia continues (pers. comm.) (pers. comm.) 5

4 Mean Max Reference 3 size 2 types 1 Mean Murrelet density Location Year Dates surveyed surveys method N. coast Graham IslandMasset InletMasset InletNaden HarbourW. Graham Island: outer coastW. Graham Island: inletsW. Moresby Island: outer coast 1977W. Moresby Island: inlets May – JunRennell SoundTasu Sound 1976 1977Sunday Inlet 128 Jun – Aug 1990 1976Pocket Inlet 1977 May – Jun 1977 4 Jun Jun – Aug May – Jun 1 May – Jun 125 1977 180 May – Jun 135 LA 42 278 1 18 1 1990 162 E–NW 1 1 1 LA 4 May – 1 Jun LA 1990 1 1990 LA 1 LA 20 Jul LA 34.2 m/l E–NW 1990 19 Jul I–OC LA 19 Jul LA E-–NW 5 I–OC I–OC 0.00 I–OC m/l 30 m/l I–OC LA – m/l 5 3.00 m/l m/l 2 1 0.00 s I–OC Vermeer and others (1983) 5.16 1 m/l – 0.00 0.09 1 LA – – 0.27 LA 0.15 – Vermeer and others (1983) – s LA I–OC Vermeer and others (1983) Vermeer and others (1983) – I–OC – Vermeer and others (1983) Vermeer and others (1983) 2.52 I–OC Rodway and others (1991) s Vermeer and others (1983) 4.19 m m Rodway and others (1991) 1.63 4.00 1.00 – – – Lawrence (pers. comm.) Lawrence (pers. comm.) Lawrence Mike InletGowgaia BayFlamingo InletLouscounne InletSkidegate InletSkidegate InletSkidegate Inlet: Long InletSkidegate ChannelCumshewa Inlet, Selwyn SoundLogan Inlet, Darwin Sound 1990 1990Laskeek Bay: nearshore 1990 1990 19 Jul 19 Jul – 1 AugLaskeek Bay: nearshore 23 – 30 JulLaskeek Bay: nearshore 22 Jul 1990 1977Laskeek Bay: nearshore 7 1977 28 Apr – 12 MayLaskeek Bay: nearshore 1990 May – Jun May – Jun 7Laskeek Bay: open water 2.5 1977 8 1990 28 Apr – 12 May 2Laskeek Bay: open water 20 May – Jun 28 Apr 30 1989Laskeek Bay: open water 115 89 1 3 4 1990Laskeek Bay: open water LA 26 May – 9 Jun 1 1991 138 11– 31 May 3 LA LA 1 1 1992 27.8 LA 2 – 18 May 44 I–OC 1993 LA 11 May – 28 Jun 1990 1 LA 20 I–OC LA 4 LA I–OC 3 May – 10 Jul 1991 I–IC 20 20 17 May – 5 Jun 1 I–OC 1992 2 May – Jun LA m 22 I–IC LS (400) 5 1993 I–IC 22 I–IC 11 May – 28 Jun 4 LA S–NW/S–IS m 2 m 22 3 May – 10 Jul 22 s I–IC 7 1.57 LS (400) m 3 s LS (400) 18.7 I–IC S–NW/S–IS LS (400) s 0.00 m/l 0.57 m/l 3 S–NW/S–IS 4 2.00 S–NW/S–IS LS (400) 9.31 (400) LS 0.75 s 5 S–NW/S–IS m/l 3.29 – s 1.00 S–OW Lawrence (pers. comm.) 0.46 0.33 s LS (400) 1.01 18.38 LS (400) s – s S–OW LS (400) Lawrence (pers. comm.) S–OW 4.03 1.78 2.18 Rodway and others (1991) Lawrence – – 1.64 S–OW 6.48 8.73 s Gaston (1989) Lawrence (pers. comm.) 1.23 20.92 Rodway and others (1991) – 3.75 s Vermeer and others (1983) Vermeer and others (1983) s 8.15 10.45 61.76 s Gaston (1991) – 5.87 Vermeer and others (1983) Gaston and Lawrence (1993) Gaston and others (1992) 2.28 Gaston and Heise (in press) 6.01 7.50 Rodway and others (1991) 2.53 3.70 Gastom (1991) 8.95 6.46 Gaston and others (1992) Gaston and Lawrence (1993) Gaston and Heise (in press) N. coast Queen Charlotte Islands W. coast Queen Charlotte Islands E. coast Queen Charlotte Islands Appendix 1—Summary of densities Marbled Murrelets reported from at–sea surveys in British Columbia May through July Region no. km No. of Survey Habitat Boat (birds per km)

USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. 309 Burger Chapter 29 Marine Distribution, Abundance, Habitats in British Columbia continues 5 4 Mean Max Reference 3 size 2 types 1 Mean Murrelet density Location Year Dates surveyed surveys method S. Laskeek Bay – Lyell IslandJuan Perez SoundS. Juan Perez Sound: nearshoreS. Juan Perez Sound: nearshoreJuan Perez–Lyell Island nearshoreS. Juan Perez Sound: open water 1992S. Juan Perez Sound: open water 17–27 JunSkincuttle Inlet 1991Skincuttle Inlet: nearshore 1992 1992 2 – 28 JulySkincuttle Inlet: open water 30 Jun – 31 Jul 1977 1991 64 31 Jun – JulPoole Inlet 1992 May – JunCollison Bay 2 – 28 July 150 50 40Houston Stewart Channel 30 Jun – 31 Jul 2 121 4 4 4Chatham Sound 5.9 6.8 1991 LS (400)Skeena Estuary 1991 30 Jun – 1 Aug S–OWPrincipe Channel 1977 1 LS (400) LS (400) LS (400) 4 4 3 –31 JulyCaamano Sound S–NW/S–IS S–NW/S–IS S–NW/S–IS 47 May – JunSurf, Racey Inlets LA 1977 LS (400) LS (400)Campania Sound s s s s 19 S–OW S–OW May – JunBoxer Reach 5 1991 87 1991 S–NW/S–ISBishop Bay 23 JulFraser Reach 5 3.91 2.30 4 Aug 8.63 3.24 LS (400) 169 m/l 1990Graham Reach s 1 s S–NW/S–ISHiekish Narrows 1990 5.60 2.94 LS (400) 9.60 15–30 May 4.90 1990“Small inlets” 1 4.72 s LA S–OW 15–30 May 12 1990 Gaston and Lawrence (1993) Sheep Pass French (1993) 1.90 3.38 French (1993) Lawrence and Backhouse (1991) 15–30 May 77 1990 27Sheep Pass 15–30 May – LA 1990 15–30 May S–NW/S–ISMussel Inlet 23 138 3.39 7.00 1 3.53 s 1Mussel Inlet 15–30 May 1 1990 m/l 63 Vermeer and others (1983) French (1993) Lawrence and Backhouse (1991) Kynoch Inlet S–NW 31 4.32 LS (400) 1 1Kynoch Inlet LS (400) 1990 15–30 May 21 0.92 1990 S–NW/S–IS LS(1000)Mathieson Channel 7.40 S–NW/S–IS 1990 Lawrence and Backhouse (1991) 1 15–30 May 1990 S–NW LS(1000)Mathieson Channel 1 15–30 May LS(800) m/l s 14 15–30 May 2.84 S–NW/S–IS s 15–30 May 1 – 1990 S–NW/S–IS LS(1000) 9 LS(1000) Lawrence and Backhouse (1991) 2.15 40 E–NW m 15–30 May m 40 1990 16.20 1 I–IC m LS(1000) Vermeer and others (1983) 9.63 9 1990 S–NW/S–IS 15–30 May – 1990 1 1 27 – 3.10 27 Jun LS(1000) 0.00 1 1990 m 0.12 – 15–30 May m F–IC 1 1991 m 21 1991 LS(600) 26–28 June Vermeer and others (1983) LS(1000) 1990 – Lawrence and Backhouse (1991) – 1 1990 3 May – 11 Jun LS(1000) – I–IC 2–23 May F–IC 1.30 Lawrence and Backhouse (1991) 19 LS(1000) 3.20 F–IC 15–30 May 33.1 15–30 May 1 29.2 0.60 F–IC 31.4 Kaiser and others (1991) m LS(1000) Kaiser and others (1991) Kaiser and others (1991) – I–IC – 1 30.7 20 1 4 60 – LS(1000) 4 m m m 0.60 F–IC Kaiser and others (1991) m 7 LS(600) Kaiser and others (1991) LS(1000) LS(600) 1 LA Kaiser and others (1991) 1 2.20 F–IC 1.44 F–IC m – 0.40 F–IC LS(600) 3.50 LS(800) m F–IC LS(1000) – F–IC – Kaiser and others (1991) – 4.10 F–IC F–IC – m m m 1.30 Kaiser and others (1991) Kaiser and others (1991) – Kaiser and others (1991) m m Kaiser and others (1991) 4.86 3.66 m m – 2.72 Kaiser and others (1991) 4.81 4.86 2.79 – Kaiser and others (1991) 4.89 2.48 0.90 Kaiser and others (1991) 11.67 6.15 Prestash and others (1992a) Kaiser and others (1991) – – Prestash and others (1992a) Kaiser and others (1991) Kaiser and others (1991) Kaiser and others (1991) Appendix 1—continued Region no. km No. of Survey Habitat Boat (birds per km) Central Mainland

310 USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. Burger Chapter 29 Marine Distribution, Abundance, Habitats in British Columbia continues 5 4 Mean Max Reference 3 size 2 types 1 Mean Murrelet density Location Year Dates surveyed surveys method Milbanke SoundMilbanke SoundQueen’s SoundFitzHugh SoundCape CautionCurrie Island – Cape MarkScott IslandsNootka Sound 1991Kyuquot Sound 1990Checleset Bay 2 May – JunBrooks Bay 1990 15–30 May 1991 1990 108Quatsino Sound 15–30 May 13 May, 1 Jun 15–30 May 1990 48Goletas Channel 3 86.7 15–30 MayQueen Charlotte Strait 34 36Johnstone Strait 1 1986 2 LS(600) 103 1991 1Baynes Sound 1991 E–NW/S–IS 13 & 23 July 1 LS(1000) 4 May - 10 July LS(1000) 1991 14 May - 26 July E–NW/S–IS 1 mDesolation Sound: Okeover Inlet LS(1000) S–NW/S–IS 56.8 83.2 28.1 LS(1000) 27 June - 26 July E–NW/S–IS 1991Jervis Inlet 1991 m S–IS/S–NW mBurrard Inlet-E. Howe Sound 29.2 LS(1000) 1991 8 May-18 June 20 June - 17 July 5 0.89 2 m 1991 9Head E–NW/S–NW m 31.7 23 May - 18 JulyIndian Arm 91.7 4.20 6 26 June-27 July m 0.21 1990 1.23 LA LA 1991Point Grey to Sandheads 72.7 LA 1991 0.10 81.3 5 9 Jun-8 Aug 0.20 4 20 May - 19 July – Prestash and others (1992a) LA 3-29 July 0.21Saanich Inlet 0.00 3 S-NW/I-OC 1991 E–NW/E–OW 1989 78.2 S-NW/I-OC – 3Sidney - Mandarte Island LA – Prestash and others (1992a) 72.4 LA m 25 May- 4 July Kaiser and others (1991) 13 - 14 Jun S-NW/I-OC s – LA s 3 37.9NW. Clayoquot Sound Kaiser and others (1991) LA 66.2 E-NW/I-OC 27 s Kaiser and others (1991) SE. Clayoquot Sound S-NW/I-OC 1987 1989 0.00 65 1989 Kaiser and others (1991) SE. Clayoquot Sound S-NW/S-IS 2 LA 1.34 s 0.17 May, June 13 - 14 Jun 2 LA I-IC/F-IC ?SE. Clayoquot Sound s 13 - 14 Jun 0.00 0.71 s 1989 2 LA 6.31 S-NW 1992 1.19 s LA 135 I-IC Burger (unpubl. data) 36 2.98 13 - 14 Jun 17.5 0.03 15 May - 28 Jul Savard and Lemon (1992) 1.18 Savard and Lemon (1992) LA 1986 S-NW 0.96 1982 S-NW/S-IS 4.63 Savard and Lemon (1992) 1.31 2 9.5 s 2 2 May - Jul 38 0.06 1982 1-25 Jun s S-NW 1.28 Savard and Lemon (1992) s 1992 Savard and Lemon (1992) 1-25 Jun 11 2.17 s LA LA LA 1993 2 0.80 Savard and Lemon (1992) 17-30 Jun 96 244.5 Savard and Lemon (1992) 16-26 Jun 5.11 LS(300) 0.86 s F-IC I-IC S-NW 646.5 2.23 1.16 LA S-NW/S-IS 586.0 6 1 11.02 586.0 1.47 Savard and Lemon (1992) 1 2.41 m 0.46 I-IC Kaiser and others (1991) 1 LS(300) GR s Savard and Lemon (1992) m s 1 Savard and Lemon (1992) F-IC GR - 2.08 GR E-NW/I-OC 0.63 2.69 GR s 0.53 S-OW/S-NW Lemon (pers. comm.) 5.05 s/m S-OW/S-NW s 0.85 s/m - S-OW/S-NW - Clowater (pers. comm.) s/m 0.08 2.27 Vermeer (1989) s/m 7.39 Lemon (pers. comm.) 0.05 Lemon (pers. comm.) 4.61 - - 4.91 - 0.10 - Lemon (pers. comm.) Sealy and Carter (1984) - Morgan (1989) Sealy and Carter (1984) Kelson and others (in press) Kelson (pers. comm.) NW. Vancouver Island NE. Vancouver Island E. Strait of Georgia W. Strait of Georgia SW. Vancouver Island Appendix 1—continued Region no. km No. of Survey Habitat Boat (birds per km)

USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. 311 Burger Chapter 29 Marine Distribution, Abundance, Habitats in British Columbia 5 4 Mean Max Reference 3 size <1 km from shore; S-IS: among sheltered islands); F = fjord (F–OC: facing d. arter 1984). 2 ounted within a 1 x km grid. To convert birds per sq. in grid censuses to km, types 1 Mean Murrelet density 19721973 8 May - 31 Jul 15 May, 5 Jun 19.2 19.2 10 2 LA LA S-IS/S-OW S-IS/S-OW s s 3.97 2.79 13.85 Hatler and others (1978) 3.07 Hatler and others (1978) 19791987 10 May – 31 Jul1989 24 Jun – 30 Jul 17.21991 14 Jun – Jul 19.5 24–31 Jul 9 19.5 3 5 LS(500) 19.5 E–NW LS(300) LS(300) 2 E–NW E–NW m LS(300) m E–NW m 8.20 1.42 m 27.48 4.08 2.84 Carter (1984) 7.98 1.18 Burger (unpubl. data) Burger (unpubl. data) 1.57 Burger (unpubl. data) 1993 13 May – 28 Jul 19.5 4 LS(300) E–NW m 0.28 0.55 Burger (unpubl. data) LA = linear transect, all birds counted; LS(x) strip transect (transect width x m); GR grid–census, c E = exposed ocean (E–OW: >1 km; E–NW: nearshore <1 km); S strait or sound (S–OW: open water km from shore; S–NW: Boat size: s = small (<6m length); m medium (6–20 m); l large (>20 m) Units of density are in birds per linear km. In some studies the densities were reported other units, but have been converte PRNP = Pacific Rim National Park 1 2 3 4 5 Location Year Dates surveyed surveys method Long Beach (Tofino-Ucluelet)Barkley Sound 1982 1-25 Jun 123.0 1982 1-25 Jun 1 GR 952.5 E-NW 1 GR s/m S-IS/S-OW 9.90 s/m - 3.58 Sealy and Carter (1984) - Sealy and Carter (1984) Barkley Sound: Broken Group IslandsBarkley Sound: Broken Group IslandsBarkley Sound: Broken Group IslandsBarkley Sound: Deer Islands 1991Barkley Sound: Deer Islands 1992 27 May - 30 JulBarkley Sound: Deer Islands 1993 4 Jun - 21 JulBarkley Sound: Trevor/Deer Islands 8.8 5 May - 27 JulBarkley Sound: Trevor/Deer IslandsBarkley Sound: Trevor/Deer Islands 8.8 1979 16 8.8Alberni Inlet - upper Trevor Channel 1986 1979 10 May - 31 Jul 10 1988 LS(400) 1992 7 14 May, 26 Jul 16 Jun - 6 Jul 31.4 1993 S-IS 2 May - 20 June 2 Jun - 26 Jul LS(400) 1988 19.7 1 May - 25 Jul 48 LS(400) 19.7 S-IS 41 May - Jul 40 S-IS 2 40 3 s LA 37 130 4 LA s 6 LA LA S-IS s 5.78 LA 4 S-IS LA 8.30 S-IS/S-OW S-IS 16.59 3.02 LA S-IS/S-OW s 21.14 PRNP wardens (pers. comm.) S-IS/S-OW s 11.70 s s PRNP wardens (pers. comm.) F-OC/S-NW s s PRNP wardens (pers. comm.) 1.15 5.54 m 4.91 3.43 5.96 10.79 - 2.81 0.67 7.70 4.83 Carter (1984) 9.45 6.85 Porter (1981) Burger (unpubl. data) Burger (unpubl. data) 1.64 Burger (unpubl. data) Burger (unpubl. data) Vermeer and Morgan (1992) Barkley Sound: Ucluelet - Broken Group Islands Barkley Sound: Ucluelet - Broken Group Islands Trevor Channel – Cape Beale Seabird Rocks Trevor Channel – Cape Beale Seabird Rocks Trevor Channel – Cape Beale Seabird Rocks Pachena BayPachena Point – Owen Pachena Point – Owen Cullite Cove to Owen PointOwen Point – Port RenfrewOwen Point – 1991 1993 2 Jun – 26 Jul 1993 17 Jun 1991 1991 49.1 20 May – 8 Jun 1993 5–7 June 2 Jun – 26 Jul 8.7 17 Jun 4 49.1 7.1 10.2 33 LA 1 4 LS(300) 2 7.1 E–NW LA E–NW LA 1 LA E–NW s I–OC s LA I–OC 14.20 m I–OC 12.08 s s 25.93 28.05 12.46 PRNP wardens (pers. comm.) m Stewart (pers. comm.) 0.94 2.94 – 1.97 1.55 – Burger (unpubl. data) PRNP wardens (pers. comm.) – PRNP wardens (pers. comm.) Burger (unpubl. data) Trevor Channel – Cape Beale Seabird Rocks Trevor Channel – Cape Beale Seabird Rocks linear distances were assumed to be 1 km per quadrat for inshore areas and 2 fjord channel quadrats (see Sealy C open coast; F–IC: facing sheltered inner coast); I = inlets (I–OC: I–IC coast) Appendix 1—continued Region no. km No. of Survey Habitat Boat (birds per km)

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