VOL. 35, NO. 1 (MARCH 1982), P. 88-1 11 Spring Migration andHabitat Use by Seabirds in Eastern and Western PETER L. MCLARENI

ABSTRACT. The status and distribution, during spring and early summer, of northern fulmars (Fulmarus glacialis), black-legged kittiwakes (Rissu rridaciylu), thick-billed murres (Uriu lomviu) and black guillemots (Cepphus grylle) were studied during aerial surveys in eastern Lancaster Sound (1976, 1978,1979)and western Baffin Bay (1978,1979).Fulmars were present in the study area by early May but most undertook a pre-laying exodus in late May before returning in early June to nest. During June and the first half of July, they were common alongcoasts and in offshore areas throughout the region. Kittiwakes returned in late May and numbers increased through June, both along coasts and offshore. Numbers offshore decreased after nesting, which begins in mid- to late June. Murres returned to the study area around mid-May and were abundant during June, especially near their colonies. Densities were generally highest along fast ice edges. Guillemots returned to the study area in the last half of Mayand were widespread along coasts, ice edges and ln offshore areas during June, Densities were much lower after nesting, which commences in late June. Densities of fulmars, murres and guillemots were much higher along fast ice edges than along ice-free coasts; the opposite was true of kittiwakes. Offshore, fulmars and kittiwakes preferred waters with little or no pack ice, whereas murres and guilleniots preferred moderate to heavy pack ice. These habitat preferences affected the distributions of the species within the region. Ice conditions in eastern Lancaster Sound were markedly different during each of the three years of study. Effects of different ice conditions on the species’ distributions are assessed. Seabird distributions in six parts of the region are summarized. Key words: fulmar, kittiwake, murre, guillemot, distribution, habitat use, Lancaster Sound, Baffin Bay

RÉSUMÉ. La position et la distribution, durant le printemps et le debut de I’CtC, des fulmars boreaux (Fulmarus glacialis),des mouettes tridactyles (Rissu triductyla), des marmettes de brunnich (Wulomviu) et des guillemots noirs (Cepphus grylle) furent ttudibes lors de releves atriens dans la partie est du detroit de Lancaster (1976, 1978, 1999)et la partie ouest de la baie de Baffh(1978, 1979). Les fulmars &aient presents dans le territoire B l’ttude au debut de mai. La majorite entreprit une excursion au large des côtes avant la periode de la ponte pour retourner B leur nid vers le debut dejuin. Durant les mois de juin etla premibre moitiede juillet, ils Ctaientgroupes le long de la c6te etau large disperses au travers la region. Les mouettes retourntrent B la fin de mai et leur nombre augmenta en juin,tant le long de la côte qu’au large. Leur nombre au large diminua aprts la nidification, laquelle commença pendant la deuxitme moitiC de juin. Les marmettes sont retournees B la zone B l’etude vers la mi-mai et elles y ttaient nombreuses durant le mois de juin, particulitrement prbs de leurs colonies. Leur demit6&ait gtndralement tlevee le long des banquises de glace fixe. Les guillemots sont retournesa la zone B I’ttude lors la seconde moitie du moi de mai et se sont repartis le long des &tes, sur les banquises de glace fixe et au large des côtes durant le mois de juin. La densite etait plus faible aprbs la nidification, laquelle commença B le fin de juin. La densite des fulmars, des marmettes et desguillemots etait plus importante le long des bordures de glace fixe que le long de la côte sans glace: le contraire etait vrai pour les mouettes. Au large, les fulmars et les mouettes ont prefer6 les eaux contenant peu ou pas de glace en derive tandis que les marmettes et les guillemots ont prefer6 les eaux B concentration moyenne ou forte de glaces en derives. Ces preferences d’habitat affectent la distribution des esphces dans la region. Les conditions de glace dans la partie est du dttroit de Lancaster ttaientdefinitivement diffkrentes durant chacune destrois annees de

I’ttude. Les effets de difftrentesconditions de elaceI sur la distribution des esptces furent evalues. La distribution des oiseaux de mer dans six secteurs de laregion est rksumee. Traduit B Petro-, St. John’s.

INTRODUCTION 1978; Thomson, 1982). However, distributions and move- Upwards of 1 O00 O00 seabirds nest along the coasts of ments of seabirds in this area are, in general, poorly known. eastern Lancaster Sound and western Baffin Bay (Brown Ship-based sea watches (Brown et al., 1975) have been et al., 1975; Gaston, 1980). Several million non-breeding restricted to the late summer-autumn period. Previous birds may spend all or part of the summer there and vast information about seabirds in spring and early summeris numbers migrate throughto nesting and summeringareas largely anecdotal and restricted to coastal observations in the central CanadianHigh Arctic and northwest Greenland(Hbrring, 1937; Shortt andPeters, 1942; Duvalland Handley, (Salomonsen, 1950; Nettleship, 1974; Brown et al., 1975; 1946, 1948; Gunn, 1949; Ellis, 1956; Pattie, 1977). Nettleship and Gaston, 1978). The principal species in- This paper, based on aerial surveys, documents the volved are the northern fulmar(Fulmarus glacialis), black- status, distribution and habitat use of four of the major legged kittiwake(Rissa triductyla), thick-billed murre(Vriu seabird species during spring and early summer (early lomvia), dovekie (Alle alle) and black guillemot (Cepphus May to mid-July). The fifth majorspecies, the dovekie, is grylle). Most nesting in the area is at several colonies discussed ina separate paper (Renaud et al., 1982). bordering Lancaster Sound and Baffin Bay (Fig. 1). Lancaster Sound and adjacentwaters are considered to METHODS be one of the most productive marineareas in the Cana- Aerial surveys of birds were conducted in all or part of dian Arctic(Nettleship and Smith, 1975; Milne and Smiley, the eastern Lancaster Sound-western Baffh Bay area in

‘LGL Limited, environmental research associates, 44 Eglinton Avenue West, Toronto, Ontario, Canada M4R 1Al EASTERN ARCTIC SEABIRD DISTRIBUTION 89

1979. From 9 May-15 July, ‘coastal’ transects were flown from Cape NortonShaw, (76’30’N), south to the HenryKatqr Peninsula on Baffh Island (69’30‘N). In addition, offshore areas of eastern Lancaster Sound and western B&lnBay were sampled (Fig. 2). 5 cambtidw Paint Coasts, ice edges and offshore eastern Lancaster Sound were surveyed at about 10-day intervals. Offshore Baffin 16 Bay wassurveyed three times in the 12-26 May period and twice in the 19-28 June period. Because of local weather and ice conditions, not all areas were surveyed regularly, and total lengths of the 75 transects differed amongsurveys. The transect width was always 400 m - 200 on either side of the aircraft. Table 1 summarizes the survey effort during each of the three years. In this paper only the spring and early summer Cqw Oraham Moore 74 (May to mid-July)distributions of the four seabird species 40,000 thick-billld murrn 6000 black-1-d kHfl*aLIs are considered. Information about the later summer and ? blackguillemots 8AFF.N fall distribution of seabirds is presented in McLaren and BAY Renaud ( 1982). 73 Survey Procedures Buchan Gulf 0.000 northwn fulmars All surveys were conducted from a twin-engine de

71’ Havilland TwinOtter equipped witha radar altimeter and

72 a Global Navigation System. Survey altitude was 45 m w Scott Inlet ASL and ground speed was kmh160 in 1976 and 185 kdh in 1978 and 1979. Aerial surveys were flown withobservers on both sides of the aircraft: one in the co-pilot’s seat and onein the left rear seat, two seats behind the pilot. In 1976 and occasion- FIG. 1. Nesting colonies of seabirds in eastern Lancaster Sound and westernBd1nBayarea. DatafromBrownetal.(1975),andS.R. Johnson, ally in 1978,a third observer was present behind the right D.N. Nettleship, W.E. Renaud (pers. comm.). front observer. Observers dictated into portable tape record- ers all birds counted both on-transect (<200 m from the aircraft) andoff-transect (>200 m from the aircraft). Infor- 1976, 1978, and 1979. The degree and areas of coverage mation recorded included systematic information about differed among years. Two main types of transects were the transect, each bird sighting,andsthe habitat belowthe flown: (1) ‘coastal’ transects, which were parallel to and aircraft at 2-min intervals. centered 200 m from coasts and iceedges; and (2) ‘offshore’ A timing device was used to divide all transects into transects, which were >7 km from anycoast or ice edge. 2-min intervals (transect segments). For each transect segment the general habitat type and the type and degree Survey Coverage of ice cover were recorded by each observer. The last 1976. From 2 May-28 September, weekly surveys were segment of a transect was oftenless than 2 min induration; conducted in eastern Lancaster Sound. The survey route its duration wasrecorded in seconds from a digital watch. consisted of eight north-south cross-soundtransects spaced This procedure permitted determination of the position of 14.8 kmapart and of ‘coastal’ transects along south Devon each sighting within about 5.3 km in 1976 and 6.2 km in Island and northwest Bylot and northBaffh islands, be- 1978 and 1979, and also permitted calculationof densities tween 80’00’W and 83’30’W (Fig. 2). on a ‘per 2 min of survey’ basis as well as a ‘per transect’ 1978. Surveys were conductedat weekly intervals from basis. On-transect counts were used to calculate apparent 4 May-10 October, except in late July and early August densities - the number of birds km-*. Usuallythe counts when the interval was about 10 days. ‘Coastal’ transects of the right front and leftrear observers were used. When were flown along coasts and ice edges bordering north- (rarely) the front observer could not observe full-time west Baffin Bay andeastern Lancaster Sound. The area of because of navigational duties, the counts of the right rear coverageextended from southeast Ellesmere Island observer were used. (76’30‘N) south to Baffin-Islandat 70’30’N. Offshore wa- ters (>7 km from any coast or ice edge)in parts of Jones Limitations and Biases of Aerial Surveys Sound, eastern Lancaster Sound, northwest Baffin Bay, Systematic aerialsurveys have been used widelyin the and werealso sampled (Fig.2). High Arctic to assess the status and distribution of birds P. L. McLAREN

GREENLAND

FIG. 2. Map of the studyGea, showing places mentioned in the text and routes surveyed repeatedly in 1976 and 1978 (left), and 1979 (right).

(e.g.,Bradstreet, 1979;McLarenandMcLaren, 1982;Renaudrelated variables suchas sun-glare, fog and precipitation. et al., 1982). However, limitations andbiases are inherent Birds are readily detectable even when quitedistant from in aerial survey techniques (see DiemLu, and 1960; Caughley an aircraft, when the sea is flat and calm;in contrast, it is andGoddard, 1972; Caughley, 1974; Caughleyetal., 1976). difficult todetect birds, particularly swimmingbirds, any- There are two primary limitationsto aerial surveys: (1) where withinthe 200-m transect strip when there are waves not all birds present are detected, and (2) recorded num- 4 m in height, a condition encountered frequently in Baffh bers of those that are detected are often estimates. Large Bay. Moreover, there may be tremendous variability in and conspicuous species are more readily observed than sea state from coasts and ice edges to offshore areas, or are smaller, inconspicuous species. Also, large flocksare even regionally withinsuch habitats. Hence detectability observed more readily than small flocksor individuals. No may vary during an individual survey. Observer ability, studies have been done to determine the proportion of fatigue, and mentalattitude also influence the number of birds that are actually observed during fixed-wing aerial birds seen. surveys of high arctic coastal waters or open ocean. Stott In addition, bird species are differentially detectable. and Olson (1972) compared simultaneous ground andaer- Male eiders in highly contrasting breeding plumage, for ial counts of sea ducks along the New England coast and example, are more easily identified than male oldsquaws. found that aerial observers saw 20-81% of the ducks pres- Patterns of behaviour also influence detectability. Molting ent. They suggestedthat detectability is poorer in coastal eiders attempt to fly or swim away from an approaching waters than in inland areas. aircraft, whereas molting oldsquaws often dive. Fulmars Detectability of birds at sea is affected by several fac- feed on the surface of the water but murresmay spend 2-3 tors, perhaps the most important of which are weather- min below the surface while diving for food. Thus, for EASTERN ARCTIC SEABIRD DISTRIBUTION 91

TABLE 1. Number of square kilometres of aerial surveys flown in eastern Lancaster Sound and western Bafb Bay, May-October 1976, 1978 and 1979

Survey Dates 2-22 23 May- 12 Jun- 3 - 15 18 Jul-16Aug- 10-28 30Sep -""May 11 Jun 2 Jul Jul 15 Aug 9 Sep Sep 10 Oct Number of surveys 3 3 1976: 3 3 3 2 4 3 0 1978: 3 3 3 2 3 2 3 3 1979: 3 1 3 2 0 0 0 0 Area" Year COASTSEAST ICE EDGES

Coburg Island areab 1978 185.8 180.1 198.8 125.2 249.8 157.1 146.6 46.4 1979 187.1 185.3 184.4 95.3 - - - -

N and E 1978 186.3 163.3 179.2 128.7 176.5 222.2 201.9 172.1 1979 114.3 116.0 123.0 36.7 - - - -

SE Devon Island 1976 144.0 147.2 156.8 109.4 278.7 258.7 252.9 - 1978 91.2 %.O 86.6 52.1 118.0 111.0 113.8 77.8 1979 88.9 66.6 72.9 64.2 - - - -

Lancaster Sound ice edge' 1978 106.4 90.8 63.6 103.0 - - - - 1979 63.4 57.0 108.8 - - - - -

N Bafh - NW Bylot islands 1976 142.3 136.7 124.9 100.8 243.3 191.2 154.2 - 1978 12.7 21.8 22.4 12.9 24.2 21.6 20.6 13.5 1979 52.6 23.2 40.3 36.6 - - - -

N & E 1978 216.8 223.4 223.5 146.0 185.7 177.4 221.3 140.2 1979 192.6 156.7 166.6 88.1 - - - -

Pond Inlet ice edge 1978 80.0 80.2 94.4 57.1 46.0 - - - 1979 78.4 23 2 35.1 9.6 - - - -

E Baffh Island 1978 295.9 282.2 406.8 245.6 321.3 4%.2 460.0 232.6 1979 365.8 206.0 430.8 224.3 - - - -

OFFSHORE AREAS

Lancaster Sound 1976 670.3 672.9 701.4 520.1 1073.9 872.3 790.2 - 1978 275.1 337.3 264.3 143.8 293.4 338.3 327.9 255.5 1979 279.5 357.8 404.1 286.7 - - -

Baffh Bay 1978 877.2 877.2 872.3 387.3 168.7 1133.3 103.7 818.3 1979 241 1.O 11%.7 1400.2 - - - 1037.0 -

a Not all areas were necessarily surveyed during each survey. , Includes coast of and fastice edges across and east of Coburg Island from 4 May - 28 July; also southeast coast of Ellesmere Island from 21 July - 10 October. There was no ice edge across Lancaster Sound in 1976. 92 P. L. McLAREN

such diving species only someof the birds actuallypresent Because of different ice conditions andsurvey patterns, on a transect strip are potentially visibleat any given time. the surveyed offshore area of eastern Lancaster Sound Estimates of numbers generally becomeless accurate as and northwest BaEn Bay was not constant for all three flock size increases. Accuracy is further reduced when years. The offshore areas (km2) withinwhich surveys several hundfeds (or thousands) of individuals of several were conducted were as follows: species of birds and mammals are in sight continuously (often simultaneously diving, swimming and taking flight). May-I12 Jun12 Jun-2 Jul 3-15 Jul Such situations are especially frequent along8289 ice edges 7800 7074EasternLancasterSound 1976 during late spring and early summer. 3689 3689I978 3689 1979 7489 7489 7489 1979 %16 Densities presented must thus be consideredas indices Northwest1978Baf!hBay 33 094 33 094 33 094 of population sizes rather than as unbiased estimates of 6631979 33 663 33 - actual numbers of individuals present. Such indices are West Baf!in Bay 1851979 948 185 948 - useful in identifying the temporal and spatial distribution Habitat Use of a species but must not be usedfor detailed quantitative comparisons of the numbers of different species, since no Information about habitat use was obtained from re- corrections for differential detectability of species have cords of the habitat encountered during each 2-min tran- been made. Furthermore, it must be recognizedthat even sect segment in 1978 and 1979. For each transect segment, for a single species, apparent differencesin densities among a broad habitat category was identified (coast, fast ice areas or surveys may bearesult of variation in detectability edge, offshore) and the average amountof pan ice cover- rather than real differences in numbers. ing the water on the transect was noted. No significant In some studies involvingaerial surveys (e.g. Nettleship differences were found in a species’ habitat preferences and Gaston, 1978) seat correction factors have been used between 1978 and 1979 and the data for both years have on the data to adjust for presumed better visibility fromthe been pooled. Differencesin habitat preference were assessed front vs. the rear seat. Although seat position per se may by chi-square contingency tests andwere regarded as influence the ability of an observer to see birds, the effects statistically significant if WO.01. of this variable are difficult to separate from effects of observer ability, the many weather-related variables, and ICE CONDITIONS the behaviours of the individual species of birds. Seat is a major factor influencing the numbers and correction factors are not used here. distributions of seabirds in arctic waters (e.g., Brown, Estimates of Numbers 1980). Changes in distribution of a species from one year to the next may in large partbe a reflection of differing ice The offshore portionof the study area was much larger than the coastal portion butthe percent coverage offshore conditions. This section summarizes the ice conditions was much lower (averages of 3.1% coverage of the off- that prevailed in eastern Lancaster Sound and western Baffin Bay during the survey periods in 1976, 1978 and shore area per survey in 1976; 1.0% in 1978 and 0.7% in 1979. Figure 2 in Renaud et al. (1982) shows the ice condi- 1979, vs. almost 100% coverage along coasts). Thus rela- tive densities may not accurately reflect the actual distri- tions in the region in late May, 1978 and 1979. bution of a species, because even low densities offshore may represent very large numbers of birds. The relative GlacierStrait-CoburgIsland-JonesSound(CoburgIs1andArea) importance of offshore and coastalareas can best be assessedThere are two major recurrent fast ice edges in this on the basis of numbers present, rather than densities. region: the ‘GlacierStrait ice edge’extends from the Marina Although itis not possibleto calculate the actual numbers Peninsula, CoburgIsland, north to near Cape Norton Shaw, of birds present (see above), rough estimates nevertheless Ellesmere Island; the ‘Jones Sound ice edge’extends north can be made, basedon calculated densities and knowledgefrom BelcherPoint, northeast Devon Island, toward King of the size of the area being sampled. Theseestimates can Edward VI1 Point, Ellesmere Island, and then southeast then be used to evaluate the distribution of a species in the to Cape Spencer, Coburg Island. The positions of these area. edges were similar in 1978 and 1979 (no surveys were I have estimated the numbers of birds present in eastern conducted here in 1976). In 1979, the Jones Sound ice edge Lancaster Sound and western Baffin Bay during each broke back to the coast of Ellesmere Island in the first survey. The density in each area was calculatedas follows: week of July, about 2-3 wk later than in 1978. Both edges, Sum of (length x density) for each transect in the area however, remained essentially intact until at least mid- July. total length of all transects in the area Northeast and East Devon Island This value wasthen multiplied bythe number of km2 inthe pertinent area to produce the estimated numberof birds in The positions of the landfast ice edge alongthese coasts the area. of Devon Island were similarin 1978 and 1979. Except for EASTERN ARCTIC SEABIRD DISTRIBUTION 93

Belcher Pointin 1979, headlands and seacliffs were virtu-vey period. Ice cover averaged 50% at the beginning of ally ice-free at their bases, whereas bays and inlets were July. covered with fast ice throughout the survey period. In early May 1979, open water extended about 30 km east of Devon Island. The remainder of northwest Baffin Lancaster Sound Bay wasice-covered, but the ice northof 74’30’N was thin Ice conditions in Lancaster Sound in the spring and refrozen pancake ice; to the south, there was heavy pack early summer were markedly different during1976, 1978 ice with a few small and often refrozen cracks. Clearing and 1979. In 1976, packed drift icecharacterized offshore proceeded rapidly from the north and west; by mid-June areas in May; by the end of June, Lancaster Sound was this entire area was virtually ice-free. essentially ice-free. A narrow band of landfast ice bor- Ice cover was significantly greater in northwest Baffin dered both coastlines until mid-June, after which most Bay in May 1978than in May 1979(Mann-Whitney U test, coasts were ice-free.1978, In fast ice covered allLancaster of P

COASTS and ICE-EDGESOFFSHORE were counted there. Numbers offshore also decreased NORTHEM FULMAR ...... during this period. On 12-15 May, the highest densities 241 . . were recorded in Lancaster Sound (Table2) but on 17-21 .. 16 :e... May densities were highest south of 70'30'N. On 24-26 May, densities andestimated numbers were low through- out western Baffin Bay. Fulmars returned to the area in early June. On 10-1 1 June, and again on19-23 June (Fig. 6), almost 12 000 were counted along coasts and ice edges - particularly along BLACK-LEGGEDKITTIWAKE Bylot and Baffh islands - and a similar number was estimated to be present in offshore Lancaster Sound. Ful- "1 mars were commonin Baftin Bay in the last half of June, I .6 especially in northwest Baffin Bay (Table 2). Coast and ice edge densitiesdecreased in late June and .8 early July, particularly in Lancaster Sound and along Bylot Island. Much of this decrease was probably due to the 1 disintegration of the fast ice edges across the sound and along northeast Bylot Island in early July. THICK-BILLEDMURRE Flock Size. Fulmars offshore in Baffin Bay in 1978 and 0 1979 were widely dispersed and generally observed as single birds (Table 3). They were seen on only16% of the 0 transect segments prior to the start of nesting in early June, but on 42% thereafter.

BLACK GUILLEMOT '.21

MAY MAY' JULYJUNE ' JUNE ' JULY '

Mean densities of seabirds recorded along coasts and fast ice edges and in offshore areas in eastern LancasterSound and western Bafh Bay, May-July 1978 and 1979. The curves are three-survey mov- ing averages.

10.0 birds km-* along coasts and ice edges (Fig. 3). Ful- mars were commonin virdually all ofthe survey area, and large concentrations were noted along northeast Bylot Island and the fast ice edge across Pond Inlet (Fig. 5). Large numbers werealso present offshore in late June and early July (Table 2), and these high numbers persisted until mid-August when concentrations beganto occur along the coast of Devon Island (McLaren and Renaud, 1982). 1979. An estimated 8000 fulmars werepresent in eastern Lancaster Sound on 9 May; 750 were counted alongsouth Devon Island andnorth and east Bylot Island. Afterthat date, however, numbers ecreased sharply (Fig. 3). From 12 May-1 June, 'coastal' 1ensities averaged 0.2 birds km'* FIG. 4. Distribution of northernfulmars in eastern Lancaster Sound and western Bafh Bay, 8-10 June 1978. Dotted lines indicate path of north of Clyde. On 17 Mdy, over 1400 fulmars were seen survey. Symbols are densities (birds/km2)in transect segments of length along the ice edgesouth of Clyde, but on24 May, only100 about 12 km (4 min of survey). EASTERN ARCTIC SEABIRD DISTRIBUTION 95

TABLE 2. Recorded densities (birds km-*) and estimated numbersof northern fulmars in offshore areas of eastern Lancaster Sound and western Baffh Bay, early May to mid-July 1976, 1978 and 1979

2-9" 9-15b 16-21 23-26 30May- 6-11 13-16 19-23 26 Jun- 4-8 9-15 May May May May 1 Jun Jun Jun Jun I Jul Jut Jul 1976 LancasterSound (0.43)(0.90)(0.31) (0.09) (0.66)(0.47) (3.66) (2.20)(5.96)(4.21)(3.27) 2193 6367 3042 637 3325 4669 28 548 25548 2846693325 637 30426367 2193 506402 49 838 32 18 236 1978 LancasterSound (2.23) (0.39)(1.25) (0.71) (2.46) (0.39) (0.30) (2.03) (0.65) (1.54) -' 5681 2398 7489 1107 1439 9075 2619 4611 1439 8226 1439 4611 2619 9075 1439 1107 7489 2398 5681 - Northwest BaffhBay (0.13) (0.50) (0.08)(0.90)(1.17)(0.82) (0.25) (0.84) (0.18) (0.10) - 548 2544 3432 5976 29 337 8152 27 284 38 767 29 806 29 767 38 4428284 278152 337 29 165976 34322544 548 - 1979 LancasterSound (1.06)(1.71)(0.23) (0.12) (0.24) (1.35) - (1.71) (1.84) - (1.19) 7935 107935 IO8 1754874 1764 12 810 - 788 12 13 793 - I1 452 Northwest Bafin Bay - (0.10) (0.23) (0.01) - - - (0.83) (3.00) - - 3433 7889 391- 7889 3433 - - 101 045 - 28 046 - - W est Baffin BayBaffin West -(0.04) (0.22) (0.12) - - - (0.27) - - - - 723314 510 230 40 - - - 51 080 - - -

a 9 May 1979. 9 May 1976, 1978. NE and E DEVON I. 'Indicates areanot surveyed. COBURG 1. AREA x1

25 Habitat Use. In May and early June, prior to nest initia- D tion, fulmars occurred in similar densities oncoastal and ice edge transects. Densities were much lower offshore (Table 4). In each of these habitats, densities decreased with increasing ice cover, although in offshore areas ful- mars were evenly distributed over waters with up to 90% LANCASTER SOUND SE DEVON 1. of ICE-EDGE ice cover, avoiding only the heaviest pack ice. :I From early June until mid-July, which includes mostof I the incubation period (Nettleship, 1977), fulmar densities were significantly higher along fast ice edges than along ice-free coasts (Table 4, X* = 126.7, df = 3, P

Discussion POND INLET : ICE-EDQE i' Fulmars that summer in the Canadian Arctic winter offshore in open-water areas in south Baffh Bay, , and the north Atlantic Ocean(Fisher, 1952; Palmer, 1962). In this study, fulmars returned to the eastern Lancaster Sound-west Bain 'Bay area in late April, and by mid-May were commonly distributed through- MAY MAVJUNE JULY JUNE JULY out much of this region. D.N. Nettleship (pers. comm.) FIG. 5. Mean densities of northern fulmars recorded in various sec- reported fulmars at the Prince colony in tions of the study area, May-July1976,1978 and 1979. Plotted as in Fig.3. P. L. McLAREN

eastern , about 250 km west of the study Fulmars returned to eastern Lancaster Sound and north- area, by the first week of May in 1976. In the latter half of ern Baffin Bay inthe first week of June. In 1978, almost May most fulmarsapparently move away from their colo-61 000 were estimated to be in this region on 8-10 June, nies. Sucha departure was notedat compared to 6000 on 23-24 May and 13 000 on 29 May-2 in 1975 (D.N. Nettleship, pers. comm.), and during this June. Their return coincides with the commencement of study few fulmars were seen at the Princess Charlotte egg-laying: the median dates of egg-laying at the Prince Monument and Buchan Gulf colonies in late May 1978. Leopold Island colony in1976 and 1978 were 10 June and This departure from the colonies (andother parts of east- 11 June, respectively (D.N. Nettleship, pers. comm.). ern Lancaster Sound and western Baffin Bay, Fig. 3) From early June on, fulmars were common in most presumably represents the pre-laying exodus (Dunnet et parts of the study area. The large flocksseen along the ice al., 1963; Macdonald, 1977), a periodwhich has been edges northeast of Coburg Island and along east Baffin associated withthe need to feed intensively atsea in order Island were likely foraging birds from nearby colonies. to acquire energy reserves necessary for egg-laying and However, the composition of the large offshore compo- incubation. Where fulmars moveat thisto time is unknown.nent is not known. Inlate June of both 1978 and 1979, an There is some indicatio that the move is not northward: increase in fulmar numbers was notedin northwest Baffh only one fulmar was se during high level (200 m ASL) Bay. Inaddition, in late June of all three years there was an reconnaissance surveys (1) coasts of southeast Ellesmere influxof fulmars into Lancaster Sound (as well as to Island and northwest G eenland and (2) offshore Baffin northeast Bylot Island in 1978 and 1979). Many of these Bay north of 76"N on 31 May-1 June 1978 (W.E. Renaud, birds, at least in 1978, may have been unsuccessful or pers. comm.). The low ;densitiesi and numbers recorded non-nesters from the colonies in Barrow Strait and Lan- even in the southernmost parts of Baff3n Bay during sur- caster Sound. D.N. Nettleship (pers. comm.) estimated veys inlate May 1979 suggest that during the exodus most that 80% of the breeding-age fulmars at Prince Leopold fulmars move completely out of the region, possibly to Island did not nest in1978. These birds would have been areas off south Baffh Iqland (Davis Strait) or, perhaps, forced to move into eastern Lancaster Sound and Baffin west Greenland.west I Bay to feed becauseof the presence of fast ice throughout EASTERN ARCTIC SEABIRD DISTRIBUTION 97

TABLE 3. Offshore distribution of seabirds in Baffin fast iceedge across the sound. The somewhathigher Bay, May-July 1978 and 1979 densities in 1979 than in 1978 may have been due to the reduced amountof pack ice offshorein 1979 (fulmars tend to avoid offshore areas with extensive pack ice). How- ever, densities offshore were much higherin 1976 than in 1978 or 1979; this may have been because birds concen- Northern 1-11 May 123 9 9 5 2.0 trated in large numbers alongthe fast ice edge across the fulmar 12-21 May 22 1220 346 91 3.7 sound when it was present in 1978 and 1979, or because 22-31 May 621 5 37 14 6.2 birds had movedinto adjacent areas of Baflin Bay inthose 1- 9 June 123 13 26 1 3 .O 10-19 June 241 33 194 21 2.9 years. 20-30 June 80044 896 230 3.8 1-10 July 109 49 177 30 3.4 BLACK-LEGGED KITTIWAKE Results Black-legged 12-21 May 1220 317 18 11.6 kittiwake 22-31 May 621 4 28 7 11.6 1976. Kittiwakes were first seen on 20 May, and were I- 9 June 17 123 34 12 3.4 present in lowdensities along south Devon Island until21 10-19 June 24 241 68 11 9.3 June (Fig. 7). Densities were substantially higherthereaf- 20-30 June 800 30 298 113 5.9 1-10 July Io9 53 83 32 5. I ter. Large flocks of kittiwakes were first seen near the Cape Hay colony on 30 May. Manythousands (e.g. 11 OOO Thick-billed 12-21 May 1210 29 529 145 11.4 on 6 June) were seen along northwest Bylot Island through- murre 22-31 May 45 621 562 243 10.9 1- 9 June 123 63 92 131 6.6 out June and July, but numbers were low west of Navy 10-19 June 67 241 208 234 5.7 Board Inlet. 20-30 June 800 60 1034 846 4.9 Large numbers of kittiwakes werefirst noted offshorein 1-10 July 109 86 168 120 3.6 Lancaster Sound on 30 May-1 June (Table 5). Densities Black 12-21 May 20 1220 209 113 4.4 were higher west of8 law; birds in that area may have been guillemot 22-31 May 24 621 139 90 4.4 migrating through the sound to nesting colonies farther 1- 9June 34 123 34 27 2.6 west. After that survey, estimated numbers offshore were 10-19 June 26 241 60 43 3.1 20-30 June 800 18 137 86 2.8 much lower. 1-10 July 109 20 18 5 3.2 1978. A few hundred kittiwakes were seen on 15-18 May, primarily near Coburg Island. On 23 May over 3500 a A transect segment represents 2 min of survey and includes about 6 were recorded near the colony at , Coburg km of transect. Island, but few were seen elsewhere along coasts. How- Excluding single birds as flocks. ever, kittiwakes beganto appear offshore at this time: an estimated 7900 were present on 22-24 May, primarily in Baffin Bay (Table 5). most of Lancaster Sound and all of BarrowStrait. Nesting Kittiwakes were common and widespread on29 May-2 success of fulmars in 1979 is not known; however,fast ice June (Fig. 8); more than 7600 were recorded. Virtually all again covered Barrow Strait and much ofLancaster Sound seen were north of Pond Inlet with flocks 600,of 300 and until mid-Julyand it is likely that birds nesting westof the 3500 near the colonies at Cape Graham Moore, Cape Hay study area, whether or not successful, would have hadto and Cambridge Point, respectively. After mid-June kitti- forage in easternmost Lancaster Sound and BanBay wakes were common and widespread throughoutthe area that year. The increase may also have consisted of, at least and ‘coastal’ densities increased in late June (Figs. 3, 7). in part, an incursion of non-breeders into the area. Sub- During this period, large concentrations briefly occurred adult fulmars werepresent along the Pond Inlet ice edgein in specificareas. Forexample, 1500 kittiwakes were along late June of 1978 (Bradstreet, 1982). the fast ice edge east of Baffh Island on 15 June and 2200 The very different iceconditions in Lancaster Sound in were along northwest Bylot Island on 19 June, but few 1976, 1978 and 1979 affected fulmar distribution in those were seen in either area again. years. Fulmar densities in the open part of Lancaster Kittiwake numbersoffshore increased in late May (Fig. Sound duringthe first half of May were similar in1978 and 3). An estimated 13 OOO were present on 30 May-I June, 1979 and about twice as high as in 1976. As well,hundreds primarily innorthwest BafEn Bay. Throughout June, den- were present along the fast ice edge across the sound in sities were generally similar Lancaster in Sound and north- 1978 and 1979. The much higherdensities in 1978 and 1979 west Bain Bay (Table 5). Numbers peaked in late June were probably caused by the complete absence of open when an estimated 44 OOO kittiwakes werepresent, prima- water west of the fast ice edge in those years. Similarly, rily in Bfiin Bay. from earlyJune to mid-July in1978 and 1979, fulmars were Kittiwake densities decreased in all areas in July (Fig. commonly seen offshore inLancaster Sound and along the 7). This drop may have beenassociated with a movement 98 P. L. McLAREN

TABLE 4. Habitat utilization bynorthern fulmars ineastern Lancaster Sound andwestern Bafk Bay, May and early June 1978, and 1979

May to early June early June to mid-July

~~~~~~~ Habitat & N~.of % of seg- # segments with densityb No.of % of seg- # segments with densityb % pack ice transect ment.9 with 0.1- 2.1- Mean transect ments"with 0.1- 2.1- Ma cover segmentsacover fulmars 0 2.1 21.5 21.5+ densityb segments'fulmars 0 2.1 21.5 21.5+ densityb

COASTS 26 2.666 1 5 11 49 1906.5 12 61 41 63 74 0-5% 47 17 9 3 5 0 1.8 69 1279.2 12 31 45 39 6 - 25% 7 14 13 0 8.7 0 1 43 47 6 14 27 0 0.7 26 - 50% 11 9 1 8 0 0 0.1 10 2 60 4 4 0 0.8 51 - 75% 29 7 2 5 0 0 0.2 33 6 4 0 2 0 2.9 76 - 90% 17 12 2 10 0 0 0.1 0- 0000 - 91 - 99% 43 7 4 3 0 0 0.2 0- 0000 - 100% 0- 0000 - 0- 0000 -

FAST ICE EDGES 34 1313 866242 1603.4 45 88 1572 193 352 786 241 13.9 0 -5% 49 392 201108 4.469 14 957 90 88 197 515 157 15.1 6 - 25% 38 102 19 63 5.214 6 88 215 25 43 116 31 12.8 25 - 50% 34 110 17 73 3.414 6 86 118 17 32 48 21 14.1 51 - 75% 32 114 16 78 2.815 5 76 92 22 26 33 11 14.3 76 - 90% 27 164 25119 2.013 7 82 83 15 24 34 10 8.7 90-99% 24 392 53298 1.634 7 75 105 26 29 39 11 7.8 100% 13 39 4 34 1 0 0.6 2 0 10 1 0 3.4

OFFSHORE 21 2509 1980456 71 2 0.3 54 1553 714 649 187 3 1.o 0-5% 36 229 63146 1 19 0.6 76 645 158 386 128 3 1.7 6 - 25% 49 80 35 41 4 0 0.4 70 159 48 78 33 0 1.1 26 - 50% 37 94 29 59 1 5 0.9 55 119 53 52 14 0 0.8 51 - 75% 25 117 25 88 4 0 0.4 31 124 85 37 2 0 0.3 76 - 90% 30 393 274102 17 0 0.4 29 265 188 69 8 0 0.4 91 - 99% 15 1370 1164186 20 0 0.1 26 212 156 54 2 0 0.3 100% 8 226 16208 2 0 0.1 10 29 26 3 0 0 <0.1

a A transect segment represents 2 min of survey and includes about 6 km of transect. Density expressed as number of birds krn-'. to nesting colonies. In1978, kittiwakes nestedin late June Moore colony and along north Bylot Island and an esti- and early July. mated 4700 birds were offshore in Lancaster Sound. 1979. Kittiwakes were first seen on 17-22May, when an After 10 June kittiwakes were common in most of the estimated 9500 were in offshore Baffh Bay, including survey area (e.g. Fig. 9); they were recordedon 94% of all almost 5000 south of 70'30'N. Over 400 were seen along transects flownfrom 10 June-15 July. Densities alongcoasts the Baffh Island ice edgesouth of the town of Clyde at that and ice edges average >15 birds km-2 during this period; time, but few wereseen along coasts and ice edges northof almost 15 000 were counted on 28 June-2 July.Concentra- Clyde. On 1 June kittiwakes were common northof Pond tions included 1700 along the Lancaster Sound ice edge, Inlet. Concentrations were noted near the Cape Graham 1500 near Cape Hay, Bylot Island, and 4700 along south EASTERN ARCTIC SEABIRD DISTRIBUTION 99

TABLE 5. Recorded densities (birds km-2) and estimated numbers of black-legged kittiwakes in offshore areas of eastern Lancaster Sound and western BaEn Bay, early May to mid-July 1976, 1978 and 1979

2-98 9-15b 16-21 23-26 30May- 6-11 13-16 19-23 26 Jun- 4-8 9-15 May May May May 1 Jun Jun Jun Jun 1 Jul Jul Jul 1976 LancasterSound (0) (0) (0.38)(0)(0.31) (1.33) (0.01) (0.80)(0.10) (0.64) (0.20) 0 0 829 05305 156071 62409408 2964 2193 1978 LancasterSound (0) (0.34)(0.63) (0)(0.88) (0.36) (0.47)(0) (0.60) (0.12) - 443 2250 1734 1325 3246 2324 1254 2324 03246 1325 0 1734 02250 443 - Northwest Baf€in Bay (1.28)(0.44)(0.51) (0)(0.17) (0.33) (0.24) (0.13) (0.02) (0.78) - 0 78001097822 105542 819 17 031 14 469 42 1% 774 25 - 1979 LancasterSound (0) (0) (0.92)(0) (0.63) (0.02) - (0.90) (1.42) - (2.43) 0 0 68580 4748 117 - 6726 10 649 - 23 374 Northwest Bafh Bay - (0) (0.03)(0.07) - - - (0.52) (1.09) - - - 0 854 185 - - - 36 17 376 669 - - West Bafh Bay - (0)(0.02) (0.05) - - - (0.09) - - - - 0 2914 9331 - - - 17 061 - - -

e 9 May 1979. 0 9 May 1976, 1978. Indicates area not surveyed. "1 NE and N DEVON I. 7 CoBURG ARFA Devon Island, all on 30 June. An estimated 46 OOO kitti- wakes were offshorein northwest Baffh Bay andeastern Lancaster Sound on 28 June-2 July. Kittiwake numbers remained high on 9-15 July. Virtu- ally all of the 10 OOO counted along coasts and ice edges ! were north of Pond Inlet. Flocks of > lo00 birds wereseen 40 SEDEVON I. near colonies on Coburg and Bylot islands, and >3500 ICE-EDGE were counted along the south coast of Devon Island. An :. estimated 23 0oO were offshore in Lancaster Sound. 20 X) Flock Size. During the initial stages of spring migration, kittiwakes offshore were seen infrequently and in flocks averaging 12 birds. By early July, however, they were

seen on more than50% of the transect segments, but most 0 birds were singles or in small flocks (Table 3). Habitat Use. During spring and early summer, kittiwake NE and E BYLOT 1. densities were significantly higher alongcoasts than along fast ice edges (X2 = 38.0, df = 3, P

northwest Baffin Bay in 1978 because of extensive ice cover. Indeed, the return of such birdsto northwest Bflh Bay in mid-June, after inspecting the colonies and finding them unsuitable for nesting, might explain the increased numbers in offshore Baffin Bay after mid-June in 1978 (Fig. 3). From mid-June through mid-July, kittiwakes were com- mon and widespread throughout muchof the survey area. Concentrations were regularly present near the colonies on Bylot and Coburg islands.There were, however, other areas where large flocks regularly occurred. In both 1978 and 1979, several thousand kittiwakes werepresent along northeast Bylot Island in the latter half of June. These birds may have included feedingbirds from coloniesto the south and west as well as late migrants moving into the area. Kittiwake concentrations werealso noted along the south- east coast of Devon Island in late June and early July of 1976 and 1979. The absence of large numbersin this area in 1978 was probablydue to the presence of a shelf of landfast ice off southeast Devon Island until earlyJuly. Kittiwakes

TABLE 6. Habitat utilization by black-legged kittiwakes in eastern Lancaster Sound andwestern BHin Bay, mid- May to mid-July 1978 and 1979

Habitat Br No, of % # segments with densityb % pack ice transect mmtsa with 0.1- 2.1- Mepn FIG. 8. Distribution of black-legged kittiwakes in eastern Lancaster cover segments" kittiwakes 0 2.1 21.5 21.5+ densityb Sound andwestern BanBay, 29 May-2 June 1978. Plottedas in Fig. 4. COASTS 205 65 205COASTS 41 71 52 41 36.7 0-5% 131 33 7637 29 32 43.2 tion route. That kittiwakes did not use this edge as a 625% 54 50 23 8 12 7 32.9 migration route earlier may have beendue to the presence 2650% 14 43 2 8 4 0 0.8 51-75% 6 33 4 0 1 '1 20.8 of heavy pack ice alongthe edge in May and early June. 7690% 4 0 4 0 0 0 0.0 The first large flocks of kittiwakes generally arrive at 91 -99% 0 - 0000- eastern and central arctic colonies at the very endof May 100% 0 - 000 0- or early June. In both1978 and 1979, large flocks were firstFAST ICE seen near the Bylot Island colonies during surveys be- EDGES 2286 54 1059 457 593 177 7.0 tween 29 May and 2 June. In 1976, large flocks began 0-5% 1161 65 408 275 373 105 8.9 arriving at their colony on Prince Leopold Island on 27 625% 286 62 108 65 85 28 7.6 May (D.N. Nettleship, pers. comm.). However, this tim- 2650% 179 56 79 30 55 15 6.1 ing may be influenced substantially by ice conditions, at 51-75% 156 45 86 32 28 10 3.9 7690% 176 37 111 31 24 10 3.5 least in western Lancaster Sound and BarrowStrait. The 90-WO 315 19 254 24 28 9 1.9 time of arrival of kittiwakes at the Prince Leopold Island 100% 13 0 13 1 1 0 0.0 colony in1978 is not known, but no birds wereseen during OFFSHORE 3227 23 2499 606 117 5 0.4 flights around the island on 26 May and 13 June (pers. 0-5% 762 48 398 288 72 4 1.0 obs.). With the exception of a lead in 625% 228 39 139 78 11 0 0.7 east of southern Somerset Island, there was in 1978 no 2650% 192 37 120 64 8 0 0.5 open water (and hence no foragingarea) west of the fast 51-75% 220 26 162 52 6 0 0.3 ice edge across Lancaster Sound prior to mid-July. Very 7690% 549 16 461 79 8 1 0.3 few kittiwakes were seen along the lead in Prince Regent 91-99% 1104 5 1052 44 8 0 0.1 100% 172 3 167 1 4 0 0.1 Inlet duringa survey there on 7 June 1978 (W.E. Renaud, pers. comm.). It appears that the kittiwakes that would normally be at coloniesiin Barrow Strait by early June * A transect segment represents 2 min of survey and includes about 6 km of transect. were forced to remain #ineastern Lancaster Sound or Density expressed as number of birds km". EASTERN ARCTIC SEABIRD DISTRIBUTION 101

FIG. 9. Distribution of black-legged" kittiwakes in eastern Lancaster Sound andwestern Baffin Bay, 10-1 1 June 1979 (left), and 28 June-2 July 1979 (right). Plotted as in Fig. 4. prefer ice-free coasts to fast ice edges. The much higher along the coast. Numbers offshore remainedhigh through densities in 1979 than in 1976 suggest that many birds in early June, averaging 70 000 murres during each of five 1976 were feeding birds from coloniesin Barrow Strait. In surveys from 10 May-7 June. Thereafter, numbers off- 1979 no open water was availablefor feeding by kittiwakes shore were much lower (Table 7). In May murres were west of Cape Warrender. widely and evenly distributed throughoutLancaster Sound. In both 1978 and 1979 kittiwake numbers offshore in In June and July, however, average densities were much Baffh Bay were highest in late June. The cause of this higher close to the Cape Hay colonyin the southeast part buildup is not known. Possibly these birds were unsuc- of the Sound. Densities were highereast of 81"" (6.0birds cessful nesters from coloniesat and westof Prince Leopold km-2) than west of 81"W (1.6 birds km-*). East of glow, Island; only 20% of the usual numberof kittiwakes nested densities were much higher inthe south half of the sound at Prince Leopold Island in 1978 (D.N. Nettleship, pers. (9.9 bird km-2) than inthe noith half (2.2 birds km-2). comm.). There isno information on kittiwakenesting Murre densities along south Devon Island averaged7.3 success at colonies in and near Barrow Strait in 1979, but birds km-2 from 16 May-5 July (Fig. 10). Densities were ice conditions at those sites were very similar in the two somewhat higher westof Cape Warrender(9.6 birds km-2). years. Thus these birds mayalso have been nestingadults Concentrations were frequently seen along the fast ice forced to forage in Baffin Bay becauseof the extensive fast edge across Croker Bay. ice covering Lancaster Sound. A third possibility is that Murres were first seen near the Cape Hay colonyon 16 these birds were immature; Salomonsen(1967) noted that May and >15 0oO were counted on 23 May. Thousands subadult kittiwakesfrom Greenland colonies wander northwere seen regularly along Bylot Island westof Cape Hay in the summer months, often moving closeto their natal during June and early July.Except for a few large flocks colonies. seen irregularly along north BaKm Island, murres were uncommon along and west of the Navy Board Inlet ice THICK-BILLEDMURRE edge. Results 1978. Anestimated 18OOmurres were offshoreLancaster in 1976. An estimated 66 OOO thick-billed murres were off- Sound on 5 May. None was seen elsewhere. By 8 May, shore in Lancaster Sound on 10-1 1 May. Few were seen however, substantial numbers had movedinto the survey 102 P. L. McLAREN

TABLE 7. Recorded densities (birds km-2) and estimated numbersof thick-billed murres in offshore areas of eastern Lancaster So$nd and western Baflin Bay, early May-mid-July 1976, 1978 and 1979

2-9" 9-15b 16-21 23-26 30May- 6-11 13-16 19-23 26 Jun- 4-8 9-15 May May May May 1 Jun Jun Jun Jun 1 Jul Jul Jul 1976 Lancaster Sound (1.36)(2.66)(0.61) (0)(7.82) (2.93)(10.18) (6.43) (9.81) (13.34) (9.30) 0 7884863673%6545947269 013 85422 60 996 47580492732211 1978 Lancaster Sound (0.49) (17.99) (13.74)(6.74) (1.01)(2.70)(3.87) (3.43) (3.78) (2.37) -' 1807 66 365 24 86424 365 180766 27614 653 12 50944 3726 874313 687 9960 - Northwest Bafh Bay (2.62)(6.60)(0)(1.43)(4.12) (1.52) (3.19) (5.14) (2.13) (4.43) - 0 146699 70 353 170 112 105 546 50 168136 336 47466 218 430 86582 - 1979 Lancaster Sound (0.42) (0.62) (0.53) (1.02) (0.25) (3.09) - (1.37) (1.67) - (3.54) 3163 4660 3957 7675 1870 23134 - 28910 12 541 - 34080 Northwest Bafh Bay - (0.27) (1.82) (4.71) - - - (0.64) (3.43) - - - 907961345 158 492 - - - 21519 115 548 - - West Barn Bay - (1.77)(0.37) (2.09) - - - (1.78) - - - - 63541 407 028 388 588 - - - 069331 - - -

" 9 May 1979. 0 9 May 1976, 1978. Indicates area not surveyed. ;EOO 1 COBURG 1. AREA xx)J NE and E DEVON 1. area. An estimated 213 000 were offshore; densities were 100 highestin Lancaster Sound (Table 7). On 22-24 May, .*...... almost 30 OOO murres wereseen along coasts and iceedges, about four times as many as on 15-18 May. Concentrations 1ww;: , were noted along the landfast ice edges in front of the colonies near Cape Graham Moore and CapeHay, Bylot SEDEVON 1. Island; along the Lancaster Sound fast ice edge; and atthe ICE-EDGE base of the murre colony at Cambridge Point, Coburg 1 Island (Fig. 11). An estimated 220 000 murres were pres- 100 I ent offshore in northwest Baffin Bay andLancaster Sound.

Numbers of murresoffshore decreased after 24 May, '00 especially in Lancaster Sound (Table 7). Numbers and -9 - 0 densities-along the ice edge across Lancaster Sound in- + 0 0 creased at the same time (although the increase was not N BAFFIN 1.- E NE and E BYLOT I. large enoughto account fully for the decrease in offshore x NAVYBOARD IN.- m waters). Murres werealso abundant along the Jones Sound 0 ice edge on 30 May. However, few birds were seen near KK) Km the colonies at Cambridge Point and Cape Graham Moore. This distribution pattern persisted until mid-June,except do*...... , that numbers decreased along the Lancaster Sound fast 0 ice edge. On 15 June, >4000 murres were present along the landfast ice edge alongeast Baffh Island; this was the 2M) 200 E BAFFIN I. first occasion whenmurres were common in that area. In ICE-EDGE contrast, relatively few murres were along the ice edge across Pond Inlet or alongBylotIsland. Do 1 Murre numbers increased in late June. Almost 40 OOO "1 murres werecounted along coasts edgesandice on 26-30 ... 0 0 June (Fig. 11); an estimated 92 OOO murres were within7 I t km of the coasts and ice edges in the survey area. An JULYJUNE MAY JULY JUNE MAY FIG. 10. Mean densities of thick-billed murres recorded in various estimated 218 Oo0 murres Were present Offshore in Baffin sections of the study area, May-July 1976, 1978 and 1979. Plotted as in Bay.Densities remained, highthrough mid-July. Areas Fig. 3. EASTERN ARCTIC SEABIRD DISTRIBUTION 103

THICK-BILLED MURRE 26 JUN 1978 - 30 JUN 1978 DENSITT - ON TRRNSCCT TOTRL COUNTS ON: 31550 ON*IfF: 36896

1 1NOIVIDURLSISQ.KH 4 x 100.00 - 1000.00 x 20.00 - 100.00 x 2.00 - 20.00 1 0.00 - 2.00 0.00

FIG. 11. Distribution of thick-billed murres in eastern LancasterSound and western BafEn Bay, 22-24 May 1978 (left), and 26-30 June 1978 (right). Plotted as in Fig. 4. where large concentrations regularly occurred in late June 19 June and 2 July (Fig. 12). Large concentrations were and early July includedthe ice edgesacross the mouth of noted near Cambridge Point(5300 murres) and along fast Jones Sound - 17 OOO on 4 July - and across Lancaster ice edges across Jones Sound (4600 murres), Lancaster Sound and Pond Inlet on 26 June - 3700 and 5700 birds, Sound (9400 murres) and Pond Inlet(1600 murres). Densi- respectively. ties along coasts and ice edges were much lowerby 9 July 1979. About 600 thick-billed murres were seen at the (Fig. 3), although - 9OOO murres were recorded in the base of the Cape Hay colony on 9 May. On 12-15 May, Coburg Island area. An estimated 360 OOO murres were murres were uncommon along coast and ice edges but offshore in Lancaster Sound and Baffh Bay on 19-23 about 77 OOO were estimated to be offshore in eastern June. Lancaster Sound and westernBaffh Bay (Table7). Murres Flock Size. During May, murres offshore in Baflin Bay were also uncommon along,coasts and ice edges on17-22 were seen on about 35% of the transect segments; the May (Fig. 4), but almost 500 OOO were estimated to be average flock size was 10-15 birds; by late June, the fre- widely distributed offshore. Densities were highestin south- quency of sightings was much higher (-8O%), but the east Baffh Bay, south of 71"N and east of 58"W.Most average flock size was less than 4 birds (Table 3). murres in that area were probably en route to nesting Habitat Use. During spring and early summer, thick-billed colonies along the west coast of Greenland. Numbers offshore were also high on 24-26 May (Table 7), but densi- murre densities were significantly higher along fast ice ties were highest in northwest Baffh Bay. edges than along ice-freecoastlines (Table 8; X' = 61.1, df Murres were abundant alongcoasts and ice edgesafter 1 = 3, P

THICK-BILLED MURRE 19 JUN 1979 - 23 JUN 1979 OENSITY - ON TRANSECT TOTRL COUNTS ON, 22362 ON+OFF: 25551

OWFIN ' ISLRNO

x 20lOO100.00 - - 100.0111000.00 x 2.00 - 20.00 L...... i 0.00 2.00 x\.I . - 0.00

FIG. 12. Distribution of thick-billed murres in eastern Lancaster Sound and western Baffin Bay, 19-23 June 1979 (left), and 28 June-2 July 1979 (right). Plotted as in Fig. 4.

Murre densities were much lower offshore (Table8). In and Nettleship, 1981). Egg-laying usually begins about 20 that habitat, however, densities were higher in light to June, although median layingdates are in late June or early heavy pack ice(6-90%) than in areas with no iceor >90% July (Gaston and Nettleship, 1981). In 1978 laying was ice. delayed about three weeks, with the peak of egg-laying occuring on 24 July at Cape Hay (L. Patterson, pers. Discussion comm.) and on 18 July at Prince Leopold Island (D.N. Thick-billed murres that summer in the eastern Cana- Nettleship, pers. comm.). Afterthe initial influx of birdsto dian Arctic spendthe winter off southwest Greenland and their colonies in late May, varying numbers werepresent Newfoundland (Tuck, 1961; Gaston, 1980). Although early in front of the colonies as prospecting birds arrived and migrants reached easterniLancaster Sound and northwest then departed again priorto laying (cf.Tuck, 1961). Thus, Baffin Bay bythe first wdek of May during thisstudy, the during June, murres were widespread and common through- major influx intothis area began about mid-May andcon- out much of eastern Lancaster Sound and western Baffin tinued throughoutMay and intoJune. In all three years of Bay. Important areas included the fast ice edges across study, estimated numbers present were highest during Jones Sound, Lancaster Sound, Navy Board Inlet, and surveys from 22-26 May. Migration was predominantly Pond Inlet, all of which are close to colonies, and pack ice offshore, at least prior to midJune. The fast ice edgeeast areas of Lancaster Sound andnorthern Bafin Bay. Murres of Baffin Island may be an important migration route in concentrate along ice edges in springto feed on arctic cod June. and other organisms (Bradstreet, 1980; Bradstreet and Large numbers of murres first appeared at colonies in Cross, 1982). the last half ofMay. Thefirst large flocks wereseen in 1978 The conditions that were responsible for the delayed near the Coburg Island, Cape,Graham Moore and Cape nesting in 1978 may also have been responsible for the Hay colonies on 23 May, 22 May and 15 May, respective- large numbers present (an estimated220 OOO birds) in off- ly. In 1976, more than 12 OOO were atthe base of the Cape shore northwest Baffh Bay in late June in that year. These Hay colony on24 May, and large numbers firstappeared birds may have been breedingadults waiting for the Prince on the cliffs at Prince Lebpold Island on23 May (Gaston Leopold Island and Cape Hay coloniesto become suitable EASTERN ARCTIC SEABIRD DISTRIBUTION 105

TABLE 8. Habitat utilization by thick-billed murres in land. Numbers offshore decreased after 9 May (Table 9), eastern Lancaster Sound and Western Baffh Bay, early presumably as birds moved to nesting areas both inside May-mid July 1978 and 1979 and outside the survey area; after the end of May only a few hundreds birds were estimated to be offshore during each survey. On 20-21 June high densities were again Habitat No. of % of seg- # segments with density % packtransect ice mentsawith 0.1- 2.1- Mean recorded along Devon Island west of Cape Warrender cover segmentsa murressegmentsa cover 0 2.1 21.5 Zl.S+ densityb (15.2 birds km-2) and along north Baflin Island(13.3 birds COASTS 222 51 109 63 31 19 11.4 km‘2), but densities were much lower in allareas thereaf- 0-5% 131 60 52 46 21 12 14.0 ter (Fig. 13). 6-25% 52 6-25% 46 28 11 8 5 9.0 1978.Guillemots werepresent north of BylotIsland on4 2650% 18 22 14 3 0 1 1.7 May. Densities and numbers remained generallyconstant 51-75% 9 51-75% 44 5 1 2 1 4.5 7690% 11 9 10 1 0 0 <0.1 through mid-May (Fig.3). However, a major movementof 91.99% 1 0 0 1 0 0 0.4 guillemots into the area had occurred by 22-24 May when 100% 0 0 0 0 0 0 0.0 an estimated 44 000 were present offshore and more than FAST ICE 2000 were seen along ice edges andcoasts (Fig. 14). Fol- EDGES 2672 73 99835.6 560722 392 lowing this major movement, densities and numbers along 03% 1248 78 26955.9 377 411 191 ‘coastal’ transects decreased (Fig. 3) and this decline con- 6-25% 301 6-25% 72 37.883 71 100 47 26-50% 214 26-50% 59 87 12.140 25 62 51-75% 1% 54 2891 42 35 13.3 764% 242 48 26.3 28125 56 33 20 COBURQ I. AREA 20 NE and E DEVON 1. 9o-99% 441 9o-99% 29 5.0 31313 51 46 0 100% 30 100% 0 30 0 0 0 0.0 OFFSHORE 381 1 49 2.81946 90 828 947 1 0 IO 0-5% 1 80 63 2.0 2946 ,188 313 6-25% 230 6-25% 71 6.2 7 6677 80 26-50% 203 26-50% 67 684.0 557 73 51-75% 229 51-75% 703.9 6 6978 76 7640% 630 60 25032 177 171 4.6 9 1-99% 14701-99% 9 35 2.0 95931 233 247 100% 248 100% 3 240 5 2 1 0.2 . LANCASTERSOUND 20 SEDEVON I. ...’*..ICE-EDQE a A transect segment represents 2 min of survey and includes about 6 km of transect. IO Density expressed as number of birds km-’. 0 oo for nesting, which in 1978 did not hamen until midJuly. Estimates-offshore in late June 1979 were only about half p those in 1978. Egg-laying at Cape Hay in 1979 started in 5 late June, with a peak in early July (Birkhead and Nettleship,g 20 N BAFF~N1.- NE and E BYLOT 1. NAVYBOARD INLET- 1981). There is no information from Prince Leopold Island2 NW WLOT 1. for 1979. Consequently, more breeding birds may have 1 0 been atthe Cape Hay colony late in June 1979 than in 1978, 0 and concomitantly, fewer would have beenoffshore. The difference between yearsmay also have been due to murres’ preference for pack ice areas rather than ice-free waters. Ice cover in northwest Baffin Bay averaged 62% on 26 June 1978, but only 4% on 28 June 1979. 20 POND INLET 20 E BAFFIN 1. ICE-EDOE BLACK GUILLEMOT 0”“ Results 1 IO ...... 1976. A few hundredguillemots were present in easternmost Lancaster Sound on 2-3 May. Several thou- 0 sands were present on 9 May, mostly offshore. On 23-24 May high densities were recorded alongsouth Devon Is- land (Fig. 13), particularly west of Cape Warrender, and FIG. 13. Mean densities of black guillemots recorded in various sec- concentrations were also seen along northwest Bylot Is- tions of the study area, May-July 1976,1978and 1979. Plotted as in Fig. 3. 106 P. L. McLAREN

TABLE 9. Recorded densities (birds km-2)and estimated numbers of guillemots in offshoreareas of eastern Lancaster Sound and western Baffh Bay, early May-mid July 1976, 1978 and 1979

2-9” 9-15b 16-21 23-26 30May- 6-11 13-16 19-23 26 Jun- 4-8 9-15 May May May May 1 Jun Jun Jun Jun lJul Jul Jul 1976 Lancaster Sound (0.06) (0.55) (0.13)(0.36)(0.24) (0.05) (0.05) (0.01) (0.04) (CO.01)(0.01) 424 3891 1698 2547 920 354 390 78 312 78 390 354 920 2547 1698 3891 424 32 83 1978 Lancaster Sound (0.33) (0.12)(0.92) (1.14)(0.50) (0.43) (0.10) (0.10) (1.52) (0.10) -‘ 1217 1846 369 5607 369 369 1586 4205 3394 443 3394 4205 1586 369 369 5607 369 1846 1217 - Northwest BaflinBay(0.10)(0.82)(0.35) (0.42) (0.21) (0.36) (1.17) (0.31) (0.54) (0.18) - 6100 17 883 10 316 38 794 11 781 7043 13 739 11 53811 739 704313 781 11 794 38 316 10 883 610017 26995 3196 - 1979 Lancaster Sound (0.19)(0.32) (0.05)(0.59) (0.18) (0.16) - (0.02)(0.08) - (0.13) 2418 1451 365 1181 1320 4402 - 586 181 - 1280 Northwest BaffinBay - (0.08) (0.38) (0.30) - - - (0.03) (0.05) - - - 2489 12 683 10 162 - - - 1036 1684 - - W est Baffin BayBaffin West - (0.13) (0.21) (0.15) - - - (0.06) - - - - 15 392 38 467 27 852 - - - 56910 - - -

a 9 May 1979. 9 May 1976, 1978. ’Indicates area not surveyed.

BLACK GUILLEMOT 19 JUN 1979 - 23 JUN 1979 OEN51TY - ON TRANSECT TOTAL COUNT5 ON2 3163 ON+OFF: 3163

BOffIN l3LONO

...... INOIVIOURLSISQ.Kl4 I INDIVIOURLS/SQ.KM 0 20.00 - 250.00 8 5.00 - 20.00 e 1.50 - 5.00 _...... 0.00 - 1.50 0.00 ,.

h

FIG. 14. Distribution of black billemots in eastern Lancaster Sound and western Baffin Bay, 22-24 May 1978 (left), and 19-23 June 1979 (right). Plotted as in Fig. 4. EASTERN ARCTIC SEABIRD DISTRIBUTION 107 tinued throughout June and the first half of July. During TABLE 10. Habitat utilization byblack guillemots in this period concentrations were seen alongthe Lancaster eastern Lancaster Sound and western Bflh Bay, early Sound ice edgein the first half of June and the northeast May to mid-July 1978 and 1979 Devon Island-Jones Sound ice edgearea in late June and early July (Fig. 13). Variable but at times large numbers X segments with densityb and densities were recorded alongthe northeast coast of Habitat & No. of % of scg- 96 pack ice transect me& with 0.1- 2.1- Ma Devon Island from May through mid-July. wvcr puiUemotssegments. 0 2.1 21.5 2'1.5+ densityb After the peak in late May, numbers of guillemots off- shore decreased sharply (Table9) and remained generally COAST 233 51 115 74 39 5 1.8 similar until late June, when a second influx apparently 0-5% 131 50 1.94265 2 22 625% 55 62 222.421 3 9 occurred. On 27-28 June estimated numbers offshore in 26-50% 18 44 10 4 4 0 1.8 Baffin Bay more thandoubled, to about 27 000 birds10 (Table 51-75% 40 3 6 1 0 0.6 9). No increase was noted in Lancaster Sound. Estimated 764% 12 50 3 6 3 0 1.2 numbers were much lower on 4-5 July. 9 1-99% 7 0 7 0 0 0 0.0 100% 0 - 00 0 0- 1979. Guillemots were presentin Lancaster Sound on 9 FAST ICE May. Almost1000 were seen along coasts and ice edges on EDGES 2816 47 1481703 483 149 3.1 12-15 May, primarily along northeast Devon Island1283 and 0-596 60 512364 304 103 4.7 the Glacier Strait ice edge. More than 3600 guillemots 625% 311 55 141 81 68 21 3.9 were counted on 20-21 May;they were very common 229 26-50% 49 117 62 38 12 2.0 along ice edgesacross Glacier Strait and Lancaster203 Sound, 51-75% 46 10955 33 6 1.8 where over 1500and 1200 birds, respectively, were recorded.7640% 250 38 156 66 25 3 1.1 9 1-99% 4981-99% 9 19 404 75 15 4 0.4 Large numbers werealso present offshore 42on 24-26 May; 100% 0 42 0 0 0 0.0 densities were highestin northwest Baffin Bay (Table 9). OFFSHORE 3995 21 3163722 109 1 0.3 Guillemots were common along coasts and ice edges 03% 810 7 75452 4 0 0.1 during June. The largest concentrations continued to be 625% 230 27 16755 8 0 0.3 seen in the Coburg Island-northeast Devon Island area 2650% 21 1 32 14365 3 0 0.3 and along the Lancaster Sound ice edge (Fig.13). 240During 51-75% 35 15574 11 0 0.4 7690% 650 35 421 1% 33 0 0.4 two surveys in the 19-30 June period, 2800 and 3100'guil-1580 91-99% 21 1251278 50 1 0.4 lemots were recorded alongcoasts and ice edges.274 Densi- 100% 1 272 2 0 0 <0.1 ties were again highest along the Glacier Strait and Lancaster Sound iceedges, although on19-23 June, higher than usual a A transect segment represents 2 min of survey and includes about 6 numbers were alsoseen along Bylot Island andthe fast ice km of transect. Density expressed as number of birds km-'. edge east of BaRn Island (Figs.13,14). Numbers offshore in June were lower than inlate May (Table 9). Densities decreased in most areas in early July (Fig.13). Discussion Almost 50% of the birds seen on 9-15 July were near the Small numbersof black guillemots winterin the North colony on the west side of Coburg Island. The Lancaster Water of northern Baln Bay and in open-water areas of Sound ice edge, where several hundred guillemots were northwest Baffin Bay (Shortt and Peters, 1942; Renaud seen regularly duringsurveys in June, had broken up by 9 and Bradstreet, 1980). However, most of those that sum- mer in the eastern Canadian Arctic probably winter in July. Guillemots that frequented the edge may have dis- open-water areas south of Baffh Bay (cf. Salomonsen, persed into offshore areas, as the density in Lancaster 1967). During this study migration into Baffh Bay was in Sound increased about sixfold between Junelate and mid- May, with the major movement occurring about 20-25 July (Table 9). May. Because the large colonies in the High Arctic are Habitat Use. Duringspring and early summer, black situated west of the survey area (Brown et ai., 1975), most guillemot densities were higher along fast ice edges than guillemots observed at this time were probablytransients. along coasts, although the difference was not significant. Indeed, numbers recorded during subsequent surveys in As withmurres, densities tended todecrease with increas- all three years did not approach those noted from 20-25 ing pan ice alongthe interface. Along fast ice edges, densi- May. Spring migration was primarily offshore; guillemots ties were higher inareas with <25% ice cover than in areas were generally absent along the Baffh Island ice edge but with >25% ice cover (X2 = 62.4, df = 3, P

During June, guillemots were widespread throughoutthe sound until the fast ice to the west broke up. In1979, the area, both along coasts and ice edges and offshore. Num-average offshore density (0.19 km-2)was much lower than bers near known colonies (Cape Hay on Bylot Island; in 1978, but in that year distribution may have been af- Coburg Island) may fluctuate markedly as prospecting fected by the almost complete absence of pack ice. birds visit nesting sites and then depart. Although the distribution of nesting sites in this area is poorly known GEOGRAPHIC SUMMARY (cf. Brown et al., 1975), the locations of some sites can be inferred from guillemot distribution duringlate June and Aerial surveys in 1976, 1978 and 1979 encompassed an early July. At this time, nesting guillemotsare likely to be area extending almost800 km north-to-south and>500 km within a few km of the nest sites. Important areas include east-to-west. Although ice conditions differed amongthe the northeast and east coast of Devon Island, the south- three years, especially in Lancaster Sound, and these west and the southeast headlands of Coburg Island(Cape differences affected seabirddistribution, it is nonetheless Spencer, MarinaPeninsulalF'rincessCharlotte Monument), possible to present a general summaryof the distributions Cape Norton Shaw on Ellesmere Island, and Cape Hay onof fulmars, kittiwakes, murres and guillemots in various Bylot Island. Concentrationsalong the ice edgeoff Buchan parts of the overall area in spring and early summer. Gulf and Scott Inlet on east Baffin Island suggest that Coburg Island Area. Northern fulmars are present in this colonies may also be situated at these sites. However, the area in early May. The largest concentrations occur near only observations of nesting coloniesin 1978 were at Prin- the Princess Charlotte Monument colony, although birds cess Charlotte Monument (an estimated 500 pairs, S.R. are also present along the Jones Sound ice edge and off- Johnson, pers. comm.) and at Cape Hay (50-100 pairs, shore in Jones Sound and Lady Ann Strait. During the W.E. Renaud, pers. comm.). In view of the consistently pre-laying exodus in the second half of May and earlyJune high densities recorded along east and northeast Devon fulmars are virtually absent but after mid-June they are Island, there is probably a substantial nesting population widely distributed throughout the area, especially along along those coastlines. On the other hand, the fairly low the fast ice edges. numbers regularly recorded alongnortheast and east Bylot Kittiwakes return to this area in late May and early Island suggest that few guillemots nest there; suitable June. They are common thereafter, both alongthe Coburg nesting habitat exists only at several of the headlands Island coast and along the two offshorefast ice edges. In along the east coast. July numbemincrease near the Cambridge Point colony In late June 1978, very large numbers of black guille- and decrease along the offshore ice edges, a reflection of mots (an estimated 27 000) were offshore in northwest the tendency of kittiwakes to remain closeto the colonies Baffh Bay; in 1979, however, <2000 were estimatedto be during nesting. present during the same period. This difference may be Murres are common in thisarea by late May and remain due to the delayed nesting season in 1978. It is possible common through mid-July. Preferredsites include fast ice that the large numbersin 1978 included breeding birdsthat edges, especially the Jones Soundice edge between had not yet movedto colonies and were forcedto wait in Ellesmere and Devon islands. Becauseof prevailing north- Baffin Bay because of the fast ice covering Lancaster westerly winds,this edge generally has littleor no pan ice Sound. As stated above, nesting was about three weeks against it. later than normalat Prince Leopold Island (D.N. Nettleship,Some black guillemots winterin parts of this area where pers. comm.), and itis logical to assume a similar delay at open water exists (Renaud and Bradstreet, 1980). The other sites. There is no information onthe chronology of major immigration occursin late May and from then through the 1979 nesting season. If it werea normal season, nesting mid-July guillemots are common and widespread. Densi- birds would have been near their colonies in late June ties and numbers are highest along fast ice edges. (although in 1979, there was no open waternear the colo- Devon Island. Northern fulmars and black-legged kitti- nies west of the study area prior to July). The amountof wakes are present along northeast and east Devon Island pack ice in Baffin Bayqay also have been a factor in the after early June. They are nowhere concentrated, but are large difference in numb rs between the two years. Like instead widely distributed throughout. Black guillemots murres, guillemots prefe offshore areas with moderateto are common along both ice edges andcoasts of northeast heavy pack ice, a condi ion present in northwest Baffin and east Devon Island after mid-May, and probably nest Bay in late June 1978; il 1979, however, that area was here. Thick-billed murres, on the other hand, are seen , i only in small numbers after early June. virtually ice-free Similarly, densities offshore in eastern Lancaster Sound Eastern Lancaster Sound. Northern fulmars are present in were about three times higher in 1978 (0.43 km'2) than in eastern Lancaster Sound by early May.By late May, very 1976 (0.19 km-2). The differencemay have been dueto the few remain; the majority undertake a pre-laying exodus presence of large numbersof guillemotsthat normally nest out of the sound. They return in early June and numbers in the central Arctic, wtjst of the study area; these birds and densities increase gradually throughJune, both along may have beenforced to; remain in the eastern part of the coasts and ice edges and offshore. In late June and early EASTERN ARCTIC SEABIRD DISTRIBUTION 109

July, several thousand fulmarsare often present along the suggests that, during their exodus, many fulmars move coasts and fast ice edges in the area. into Davis Strait. Numbers increase again in June, and Kittiwakes return to Lancaster'Sound in late May and very large numbers are present in the northwest in late early June. Initially, at least, most individuals are off- June. shore, possibly migrating to colonies west of the study Black-legged kittiwakes migrateon a broad frontacross area. After the first week of June, thousands are present Baffh Bay. Peak spring migrationis in late May and early along northwest Bylot Island. In 1976 and 1979, large June. Like fulmars, many kittiwakesare present offshore concentrations of kittiwakes were seen regularly from in Baflin Bay in late June. mid-June to mid-July along the south coast of Devon Island.Hundreds of thousands of thick-billed murres are pres- Murres return to eastern Lancaster Sound in the first ent offshore in Bafh Bay from mid-Mayonward. During half of May. Initially most stay offshore, although the migration in May they occur in a small number of large numbers present may depend on the amount of pack ice. flocks and are widespread throughout Bafin Bay. After After mid-May numbers offshore decrease, but murres migration they are seen more frequently but in smaller become common along the coasts and ice edges. In both numbers, and most are in the northwest. 1978 and 1979 many thousands were regularly seen along Thousands of black guillemots are present offshore in the ice edge across Lancaster Sound and nearthe colony Bafin Bay during migration in May. Numbers probably west of Cape Hay. decrease thereafter, although an estimated 28 OOO guille- Black guillemotsare present in eastern Lancaster Sound mots were present in the northwest in late June 1978. in early May. (In fact, small numbers winterin areas with open water [Renaud and Bradstreet, 19801.) Peak spring migration occurs during the last third of May, mostly CONCLUDING REMARKS offshore. Most of these birds are likely transients moving Although seabirds are widely distributed throughout the to the large nesting colonies to the west. Guillemots are eastern Arctic in the spring and early summer,their distri- common alongfast ice edges in eastern Lancaster Sound butions vary both temporally and spatially, primarily in from late May until the end of June. Relatively few are response to avariety ofphysical, especially ice, conditions. present along ice-free coastlines. During spring migration, enormous numbers of birds Bylot Island. Kittiwakes, murres and guillemots all ar- are offshore. In addition to those discussed in this paper, rive at the Cape Graham Moore colonyon southeast Bylot glaucous gulls(hrus hyperboreus), Thayer's gulls (L.rhayeri), Island in mid- to late May. During June, all three species ivory gulls(Pagophila ebumea), arctic terns(Srernupuradisaea) are common alongthe entire north and east coasts. Peak and dovekies (Aflede) also migrate north offshore(pers. numbers are present during the last half of June. Northern obs.; Renaud et af.,1982). Their distributions at this time fulmars are uncommon along Bylot Island in May.June In depend to a large degree on the presence or absence of and the first half of July, however, they are common along pack ice. Fulmars and kittiwakes (and other gulls) are the entire north and east coast. surface feeders and tendto occur in areas where pack ice Pond Inlet - East BaBn Island ice edge. In June, the ice is not extensive. Alcids, on the other hand, associate with edge east of Baffh Island is a migration route for black- moderate to heavy pack ice. Renaudetal. (1982) attributed legged kittiwakes and thick-billed murres. After migra- the small numberof dovekies in eastern Lancaster Sound . tion, fulmars, murres and guillemots are commonalong and northwest Baffh Bay in 1979, as opposed to 1978, to the edge. Thesebirds are presumably foraging and maybe the unusually small amount of pack ice present there in breeding birds from nearby colonies onBaffh and Bylot 1979. Although trophic relationships have not beenstud- islands, although some non-breeding fulmars have been ied in offshoreareas, some alcids may attractedbe to pack recorded along the Pond Inlet ice edge. Numbers and ice by food availability. Arctic cod(Boreogadus saida)and distributions of birds in this area during June and early the amphipod Apherusa gfacialis,two important food items July are in large part a function of the amount of pack ice of some murres and other alcids, often occur at the under- against the edge. surface of pack ice (Cross, 1982). Offshore BaBn Bay.The largest partof the survey area In addition to birds offshore, enormous flocksalso feed consists of offshore areas of Baffin Bay. Although densi- along fast ice edges and coasts in the spring. Fulmars, ties of birds are generally low offshore, the very largearea murres and guillemotsare the main species along iceedges. involved means that total numbers of birds offshore are Bradstreet (1980, 1982) and Bradstreet and Cross (1982) often high -frequently higherthan in coastal areas. Birds documented the under-ice community and trophic rela- offshore are generally widely dispersed andtheir distribu- tionships along fast ice edges. Coastal species include tion is often related to the prevailing ice conditions. oldsquaws and eiders which require shallow waters for Northern fulmars are widespread throughoutBaffh Bay benthic feeding. The presence of fast ice along coastlines in early May. During the pre-laying exodus in the second may make potential feeding areas of these species inac- half of May, most appear to leave the area; the somewhat cessible, and substantially affect their distributions (McLaren higher density recorded in south Baffln Bay at this time and McLaren, 1982). 110 P. L. McLAREN

- -

especially noticeable in kittiwakes andother gulls, which ~ Strait area, N.W.T. during spring: diets and?od availability along ice are rarely seen far offshore after mid-July (pers. obs.). edges. Canadian Journal of Zoology 58:2120-2140. -. 1982. Occurrence, habitat use, and behavior of seabirds, marine Some decrease in numbers Offulmarsand mammals, and arctic cod at the Pond Inlet ice edge. Arctic 35 (this offshore also occurs as the breeding season commences, issue). large numbersof these species may still be found offshore.- and CROSS, W., 1982. Trophic relationships at high arctic ice The age and sex compositionof the offshore component is edges. Arctic 35 (this BROWN, R.G.B. 1980, Seabirds as marine animals. In: Burger, J. etal. not known but may foraging breeders and [eds.]. Behavior of Marine Animals. Vol. 4. NewYork: Plenum breeding adults, andmay be augmented byan influx of Publishing cow.1-39. subadult birds in late June (cf. Bradstreet, 1982). -, NETTLESHIP, D.N., GERMAIN, P.,TULL, C.E. and The large numbersof birds offshorein northwest Bafin DAVIS, T. 1975. Atlas of Eastern Canadian Seabirds. Canadian Wildlife Service, Ottawa. p. Bay in late June 1978 may have beena consequence of the 220 CAUGHLEY, G. 1974. Bias in aerial survey. Journal of Wildlife Man- unusual ice conditions in Lancaster Sound (i.e., almost agement 38:921-933. total ice cover) in that year. Birds that normally forage -and GODDARD, J. 1972. Improving the estimates from inaccu- throughout Lancaster Sound inJune and July were forced rate censuses. Journal of Wildlife Management 36:135-140. to move to the easternmost areas of Lancaster Sound and CAUGHLEY, G., SINCLAIR, R. and SCOTT-KEMMIS, D. 1976. Experiments in aerial survey. Journal of Wildlife Management to Baffin Bay. 40~290-308. Seabird densities in Baffin Bay and eastern Lancaster CROSS, W.E. 1982. Under-ice biota at the Pond Inlet ice edge and in Sound are substantially higher than in areas to the west adjacent fast ice areas during spring. Arctic 35 (this issue). (pers. obs.; W.E. Renaud, pers. comm.). Although some DIEM, K.L. andLU, K.H.1960. Factorsinfluencingwaterfowlcensuses of the seabirds seen during this study were transients in the parklands, Alberta, Canada. Journal of Wildlife Management 24~113-133. moving to colonies westof the study area and Greenland, DUNNET, G.M., ANDERSON, A. and CORMACK, R.M. 1963. A most probably bred in the study area. Colonies are both study of survival of adult fulmars with observations on the pre-laying more numerous and largerin eastern Lancaster Sound and exodus. British Birds 56:2-18. Bafin Bay than in areas to the west. The generalabsence DUVALL, A.J. and HANDLEY, C.O. 1946. Report of a wildlife recon- naissance of the eastern Canadian Arctic. Special Report, United of colonies westof Lancaster Sound is likelydue to (a) the States Department of the Interior, Fish and Wildlife Service, manu- absence of suitable nest sites and (b) the typical presence script report. 138 p. of multi-year ice and complete ice cover, which would -. 1948. Second wildlife reconnaissance of the eastern Canadian eliminate any feedingareas, for much of the year. These Arctic. Special Report, United States Department of the Interior, Fish and Wildlife Service, manuscript report. 168 p. two conditions are not found in the eastern Arctic. ELLIS, D.V. 1956. Observations on the migration, distribution and breeding of birds in the Canadian Arctic during 1954 and 1955. Dansk Ornithologisk Forenings Tidsskrift 50:207-230. ACKNOWLEDGEMENTS FISHER, J. 1952. The Fulmar. The New Naturalist. London: Collins. This study was funded by Norlands Petroleums Ltd. in 1976 496 p. and by Petro-Canada Exploration, Inc. (as part of the Eastern GASTON, A.J. 1980. Populations, movements and wintering areas of Arctic Marine Environmental Studies [EAMES]) in 1978 and thick-billed murres (Uria lomvia) in eastern Canada. Canadian Wild- 1979. I thank A.T.C. Rutgers of Norlands and G.T. Glazier and life Service, Ottawa. Progress Note 110. 10p. H. Hume of Petro-Canada for theirassistance. Logistic support -and NETTLESHIP, D.N. 1981. The thick-billed murres Uria was provided by Dr. Rutgers andby G. Koenig and S. Mackenzie lomvia on Prince Leopold Island -a study of the breeding ecology of of Petro-Canada. I especially thank the pilots of Petro-Canada a colonial, high arctic seabird. Canadian Wildlife Service Monograph and of Kenn Borek AirLtd., who capably flew the surveys. The Series No. 6. Ottawa. 350 p. field work was conducted by the author and by W.E. Renaud, GODFREY, W.E. 1966. The birds of Canada. National Museums of W.R. Koski, S.R. Johnson, W.G. Johnston, R.E. Salter, M.A. Canada Bulletin 203.428 p. Gollop, L.A. Patterson, P.D. Hollingdale, and K.J. Finley of GUNN, W.W.H. 1949. Report on wildlife observations, arctic weather LGL Ltd. R.A. Davis and W.J. Richardson of LGL Ltd. pro- station re-supply mission, July 15 to September 7, 1949.MS Rep. to vided assistance and guidance in planning and data analysis. Dominion Wildlife Service, Department of Mines and Resources. W.J. Richardson, C. Holdsworth, M. McLaren, B. DeLong and 58 p. B. Griffen of LGL Ltd. helped in many ways in preparationof the HgRRING, R. 1937. Birds collected on the Fifth Thule expedition. In: manuscript. D.N. Nettleship of the Canadian Wildlife Service, Report of the Fifth Thule expedition, 1921-1924.Part 2: Zoology. P. Latour, formerly of the Northwest Territories Fish and Wild- Copehagen. 1-133. life Service, and M.S.W. Bradstreet, S.R. Johnson andL. Patterson MacDONALD,M.A. 1977.Thepre-layingexodusofthefulmar(Fulmarus of LGL Ltd. provided data pertainingto arctic seabirds. glacialis L.). Ornis Scandinavica 8:33-37. McLAREN, P.L. and McLAREN, M.A. 1982. Waterfowl populations in eastern Lancaster Sound and western Baffin Bay. Arctic 35 (this REFERENCES issue). BIRKHEAD, T.R. and NETTLESHIP, D.N. 1981. Reproductive biol- McLAREN, P.L. and RENAUD, W.E. 1982. Seabird concentrations in ogy ofthick-billed murres (uria lomvia): an inter-colony comparison. late summeralong the coasts ofDevon andEllesmere islands, N.W.T. Auk 98~258-269. Arctic 35 (this issue). EASTERN ARCTIC SEABIRD DISTRIBUTION 111

MILNE, A.R. and SMILEY, B.D. 1978. Offshore drilling in Lancaster Island, Canada: A High Arctic Ecosystem. Edmonton: University of Sound: possible environmental hazards. Institute of Ocean Sciences, Alberta Press. 413-436. Department of Fisheries and Environment, Sidney, B.C. 95 p. RENAUD, W.E. and BRADSTREET, M.S.W. 1980. Late winterdistri- NETTLESHIP, D.N. 1974. Seabird colonies and distributions around bution of black demots(CePPhus gQ'/le) in northern BaEn Bay and Devon Island and vicinity. Arctic 27:95-103. the Canadian High Arctic. Canadian Field-Naturalist 94:421-425. RENAUD, W.E., MCLAREN, P.L. and JOHNSON, S.R. 1982. The -. 1977. Studies of seabirds at Prince Leopold Island and vicinity, dovekie (Alle as a spring migrant in eastern Lancaster Sound and Northwest Territories: preliminary report of biologicalinvestigations Bafin B~~.Arctic 35 (this issue). in 1975. Canadian Wildlife Service Progress Note No. 73. 11 p. SALOMONSEN,F. 1950. The Birds of Greenland.Copenhagen: -and GASTON, A.J. 1978. Patterns of pelagic distribution of Munksgaard. 608 p. seabirds in western Lancaster Sound and Barrow Strait, Northwest -. 1%7. Fuglene p%Gr#nland. Copenhagen: Rhodos. 341 p. Territories, in August and September 1976. Occasional Paper No. 39, Canadian Wildlife Service, Ottawa. 40 p. SHORTT, T.M. and PETERS, H.S. 1942. Some recent bird records from Canada's eastern Arctic. Canadian Journal of Research 20:338-348. NETTLESHIP, D.N. and SMITH, P.A. [eds.l.1975. Ecological sites in STOR, R.S. and OLSON, D.p. 1972. An evaluation of waterfowl . Canadian Committee for the International Biologi- surveys on the New Hampshire coastline.Journal of Wildlife Man- cal Programme. Conservation Terrestrial-Panel 9.330 p. agrement 36:468-477. PALMER, R.S. [ed.]. 1962. HandbookofNorth American Birds. VOl. 1. TH&SON, D,H. 1982. Marine benthos in the eastern Canadian High Loons through Flamingos. New Haven and London: Yale University Arctic: Multivariate analyses of standing crop and community strut- Press. 567 p. ture. Arctic 39 (this issue). PATTIE, D.L. 1977. Population levels and bioenergetics of arctic birds TUCK, L.M. 1961. The murres: their distribution, populations and biol- onTrueloveLowland. In: Bliss,L.C. [ed.]. TrueloveLowland, Devon ogy. Canadian Wildlife Service Monograph Series No. 1. 260 p.