Breeding Biology of the Rhinoceros Auklet in Washington’

TheCondor88:143-155 0 The Cooper Ornithological Society 1986

BREEDING BIOLOGY OF THE RHINOCEROS AUKLET IN WASHINGTON’

ULRICH W. WILSON U.S. Fish and Wildlife Service,Nisqually National Wildrif Refuge, 100 Brown Farm Rd., Olympia, WA 98506

DAVID A. MANUWAL Wildrife ScienceGroup, Collegeof Forest Resources,University of Washington,Seattle, WA 98195

Abstract. During 1914 through 1983, we investigated the breeding biology of the Rhinoceros Auklet (Cerorhincamonocerata) at three main colony siteson the coastof Washington:Destruction Island (offshore) and Protection and Smith islands (inland islands of the Strait of Juan de Fuca). Averageburrow densitieswere higher offshore,where the aukletsnested on shrub-coveredslopes; inland aukletsnested on grassyslopes and level areas.Egg-laying patterns varied among years and populations,although initiation dates on all islandswere similar. The incubation periods averaged 45 days and ranged from 39 to 52 days. Chicks were brooded, on average,for 3.9 days (rangezero to 9 days). On Protection Island, early-hatched young grew more rapidly than chicks hatched at a later date. Chicks on offshore islands were fed a variety of fish, whereas those on inland islands were fed primarily two species.The inland chicks were fed heavier fish loads, reachedheavier peak body weights, and were heavier when they fledgedthan were offshore chicks. Breeding successwas higher on the inland colony sites. Key words: RhinocerosAuklet; Cerorhinca monocerata; Washington(state); breeding biology; pujins.

INTRODUCTION DESCRIPTION OF STUDY SITES Among the Pacific alcids, the puffins show Destruction Island (47”40’N, 124”24’W) is lo- strong structural (Storer 1945) and ecological cated 4.8 km west of the Olympic Peninsula similarities that provide an opportunity to ex- and 29 km south-southeastof La Push, Wash- amine the species’ responsesto their environ- ington (Fig. 1). The 0. 15-km2 island, part of ment. Most published accounts of these birds an extensive sandstone reef, forms a nearly reflect studiesat single colony sites.We report level terrace approximately 30 m high, with here a comparative study of the breeding bi- abrupt cliffs and steep slopeson all sides. Ex- ology of one of these puffins, the Rhinoceros tensive rocky outcroppings entirely surround Auklet (Cerorhinca monoceruta), at three dif- the island. The vegetation on the top of the ferent major colony sites in Washington State. island consistsmostly of salmonberry (Rubus Marine birds that nest on islands differing spectabilis)and salal (Gaultheriashallon), and in physiography and marine environment can is devoid of much understory. The surround- be expectedto differ among colonies in aspects ing slopesand cliffs have interspersedpatches of their biology. The breeding distribution of of salal and salmonberry, coast willow (Mix the Rhinoceros Auklet in Washington is ide- hookeriana),dune wildrye (Elymusmollis) and ally suited for comparisonsof colonies because grassassociations dominated by common vel- approximately half of the state’s auklets nest vetgrass(Holcus lunatus), orchardgrass (Dac- off the outer coast of the Olympic Peninsula, tylis glomerata),and red fescue (FestucaYU- while the remainder nest in the inshore waters bra).Mean annual precipitation for the area is of the eastern Strait of Juan de Fuca. The two 267 cm. Destruction Island is jointly admin- populations may thus experience different en- istered by the U.S. Coast Guard, which main- vironmental influencesthat are not masked by tains a lighthouse and other navigational aids latitudinal effects. on the island, and the U.S. Fish and Wildlife Our specific objectives were (1) to gain new Service. information on the major aspectsof the breed- Protection Island (48”08’N, 122”55’W) lies ing biology of the Rhinoceros Auklet, (2) to 3.2 km off the mouth of Discovery Bay at the document the responsesof individual colonies southeasternend of the Strait of Juan de Fuca to terrestrial and marine components of their (Fig. 1). About 80% of the island’s 1.59 km* environment, and (3) to compare the breeding area consistsof a plateau bounded by precip- biology of the Rhinoceros Auklet with that of itous cliffs 35 to 76 m high. At the southeastern the other two Pacific puffins. and southwesternends, extensive grassyslopes terminate in sand and gravel spits. The vegetation of this plateau area consists of mixed 1Received 30 January 1984. Final acceptance4 Decem- coniferous woods and thickets of flowering ber 1985. shrubs, grassy areas, alfalfa fields, and sand

11431 144 ULRICH W. WILSON AND DAVID A. MANUWAL

ner (1976) on Destruction Island in 1974 and 1975, and by Wilson on Protection Island in 1975 and 1976. Food habits, growth of chicks, and habitat preferences were further investigated by Wilson during short visits to Destruc- tion and Protection islands during 1979 through 1981 andin 1983. The distributions and densities of auklet burrows were determined either by counting all burrows or by obtaining average burrow densities for specific habitat types using ran- domly spacedquadrats that varied in size from WASHINGTON 3 x 3 m to 10 x 10 m. On Protection Island, the slope was measured by placing an Abney level on the top of a two-by-four that was laid acrossthe center of each quadrat; burrow occupancy patterns were determined by placing toothpicks on the entrancesof auklet burrows. Becausewe saw no evidence that small mam- FIGURE 1. Locations of Rhinoceros Auklet study sites mals inhabited the nesting areas, we assumed in Washington. that a pushed-over toothpick indicated that an auklet had entered the burrow. There is some evidence, however, that sub-adults may visit dunes. The vegetation of the grassyslopes and colony sites,although they do so generally after the more level, adjacent, peripheral areas con- the main breeding is over (pers. observ.; Ver- sistsprimarily of annual grasses,with Bromus meer, in litt.). rigidis dominating other Bromusand Aspris We investigated activity patterns by record- grasses(Richardson 196 1). Protection Island ing the daily arrival time of the first auklet that lies in the rain shadow of the Olympic Moun- we observed flying to the colony site. Fur- tains and, consequently,has an annual precip- thermore, we attempted to quantify arrival and itation of only about 41 cm. Approximately departure flights throughout the 1976 breeding 85% of the island was privately owned at the seasonby erectinga blind in a major flight path time of our study. In recent years, numerous below approximately 500 burrows that were recreational homes have been built on the pri- located on a gradual slope at the southern end vate portion of the island. Under recent leg- of Protection Island. Since Rhinoceros Auklets islation, the private portion of the island will make a characteristicwhistling sound with their be acquired by the U.S. Fish and Wildlife Ser- wings when they fly, we could count the num- vice and will become part of the refuge system. ber of arrivals and departures every 15 min The remaining 15% comprisesthe Zella Schultz throughout the night at approximately two- Seabird Sanctuary, administered by the Wash- week intervals. Becausehigh winds, rain, and ington Department of Game. pounding surf drown out the soundsof flying Smith Island (48”19’N, 122”5 1’W) is situ- auklets, this part of the study was limited to ated 16.5 km northeast of Protection Island, relatively calm nights. in the Strait of Juan de Fuca (Fig. 1). With the We determined egg-layingdates, incubation exception of several denseshrub thickets, most periods, and dates of hatching and fledging in of the approximately 0.25-km2 island is cov- the following manner: a sample of burrows was ered by beachgrassand various exotic grasses. staked, numbered, and excavated before the The island has a somewhat triangular shape onset of egg laying. Excavation was done in with a rapidly eroding cliff about 15 m in height the manner described by Manuwal (1974). on the western and southern sides. The top During the spring, the sample burrows were slopes gradually toward the east and termi- checked daily for the presence of auklets and nates in a sandy point. Annual precipitation is eggs.When an incubating bird was found, the approximately the same as at Protection Is- eggdate was recorded and the burrow was left land. Smith Island is also administered by both undisturbed for 45 days, after which time the the U.S. Coast Guard and the U.S. Fish and burrow wassearched for the presenceof a chick. Wildlife Service. If incubation was still in progress,the burrow was not checked again for another five days. METHODS Observations of chick developmental patterns Rhinoceros Auklets were studied by Manuwal were made daily throughout the nestling pe- and Wilson on Smith Island in 1974, by Lesch- riod during 1974 to 1976. Chicks were con- RHINOCEROS AUIUET IN WASHINGTON 145

TABLE 1. Use of nestinghabitat by Rhinoceros Auklets on Destruction, Protection, and Smith islands, Washington.

Mean burrow density Number of burrows Perwn; of Sampled area Habitat type (burrows/m’) on island WI Destruction Island (23,621 burrows) Cliffs/steep slopes 0.13 1,167 4.9 1,200 Grass-coveredslopes 0.47 3,938 16.7 768 Shrub-covered slopes 0.99 10,290 43.6 167 Willow-covered slopes 0.59 2,395 10.1 167 Dunegrass-coveredslopes 0.74 5,023 21.3 180 Shrub-coveredlevel edge 0.06 808 3.4 177 Protection Island (27,549 burrows) Cliffs/steep slopes 0.04 1,076 3.9 direct count Grass-coveredslopes 0.50 23,356 84.8 540 Grass-coveredlevel edge 0.15 3,117 11.3 direct count Smith Island (1,194 burrows) Cliffs/steep slopes 0.04 320 26.8 direct count Grass-coveredlevel edge 0.12 874 73.2 direct count sideredto have fledgedwhen they disappeared ing and again 12 to 14 days later. From these from their burrows. data, composite growth curves were construct- We collected food samples at night from ed accordingto Ricklefs and White (1975) and adult auklets returning to feed their chicks by k values were computed following Ricklefs’ scaringthe birds as they approached the bur- (1967) method. rows, causing them to drop their fish. After We studied breeding successby following each load was collected, the surroundingvege- the fates of eggsand chicksin marked burrows. tation was carefully searchedto ensure that no The proportion of burrows that contained eggs fish were overlooked. The prey speciescom- was determined from a sample of burrows ex- position and total load weight, as well as the cavated before egg laying and checked daily lengths and weights of individual prey items, until an egg was found. Because disturbance were recorded for each food load. Food sam- during incubation often causesdesertion in al- ples were collected throughout the nestling pe- cids (Manuwal 1974) hatching success,as in- riods on Destruction Island in 1974 (Leschner dicated by these burrows, was not indicative 1976) on Protection Island in 1975 and 1976, of natural conditions. To eliminate the dis- and on Smith Island in 1974, but only for por- turbance factor introduced by burrow checks tions of the nestling period. In 1979 to 198 1, during egglaying, we checked a sample of pre- food loads were collected during two nights viously undisturbed burrows for chicks after just after hatching and again just before the the hatching period. To make sure that exca- onset of fledging on Destruction and Protec- vated burrows did not deter breeding auklets, tion islands.The El Niiio phenomenon of 1982 a sample of burrows was excavated before egg to 1983 prompted us to collect food loads on laying and was not checked again until after Destruction Island on 12 and 13 July, and on hatching. The percentage of pairs that pro- Protection Island on 2 1 and 22 July, of 1983. duced chicks from theseburrows did not differ Names of fishesfollow Hart (1973). markedly from those percentages in undis- Chickswere obtained from burrows that were turbed burrows, indicating that breeders did excavated before egg laying, as previously de- not discriminate between excavated and non- scribed. In 1974 to 1976, daily measurements excavated nest sites. were taken of the weight, flattened wing, tarsus, and culmen. Chicks were weighed with a 200-g RESULTS or 500-g Pesola scale,depending on their size. Culmen and tarsuslengths were measuredwith NESTING HABITAT metric calipers, and a metric ruler was used to Destruction Island offered a much wider va- obtain wing measurements. Growth was ana- riety of nesting habitats than did either Pro- lyzed by fitting weight data to the Gompertz tection Island or Smith Island (Table 1). On curve according to Ricklefs’ (1967) graphical Destruction Island, the highest percentage of method of fitting equations to growth curves. birds nested on salmonberry- and salal-cov- Chick growth was further investigated on De- ered slopes,where burrow densities averaged struction Island and Protection Island in 1979 0.99 burrows/m2. Dunegrass-, willow-, and to 198 1 by weighing a sample of chicks (ap- grass-covered slopes were also used exten- proximately 20 per year per island) after hatch- sively, with average burrow densities of 0.74, 146 ULRICH W. WILSON AND DAVID A. MANUWAL

I April May JWle July August FIGURE 2. Seasonalburrow occupancyof Rhinoceros Auklets on Protection Island. ;+, Sunset

0 Protection Island 0.59 and 0.47 burrowsIm2, respectively. Cliffs A Smith Island and steepslopes, as well as the dense salal- and C Destruction Island salmonberry-covered upper level edge of the FIGURE 3. Nightly arrival times of first Rhinoceros island, were used by only a small number of Auklets landing on colony, Destruction Island, Smith Is- birds. land, and Protection Island (Destruction Island data from On Protection Island, the largestof the three Leschner 1976). colonies, 85% of the auklet population nested on the grass-coveredsoutheastern and south- several days between 20 and 26 April. This westernslopes. Burrow densitieson theseslopes initial occupancy, which may have been spo- averaged 0.50 burrows/m2, compared to 0.47 radic, was followed by a period of general ab- for this habitat type on Destruction Island. The sencethat was usually terminated when an egg rest of Protection Island auklets nested within was laid in the burrow. The duration of this the less-preferredlevel or cliff habitats. Burrow absencevaried between 6 and 35 days. A few density was significantly correlated with angle burrows, however, did not follow this pattern. of slope (P < 0.001, r = 0.633, 80 df) on Pro- Some were occupied almost continuously, tection Island. whereasothers were occupied sporadically be- The areas that were used by nesting auklets tween the time of first occupation and the day on Smith and Protection islands were similar when the egg was laid. in vegetation coverage and burrow density. These findings indicate that Rhinoceros Most of Smith Island’s small auklet population Auklets arrived at the colony site at about the nestedalong the flat, grass-coveredupper edge same date each year, when they spent a brief of the island. This colony has little potential period cleaning out the old burrows or digging for expansionbecause it lacksmoderate slopes. new ones. Most of the breeding pairs then departed the area of the colony and spent some SEASONAL COLONY ATTENDANCE time at seabefore returning for egglaying. The Seasonal colony attendance, as indicated by duration of this period of absencevaried among burrow occupancy, was investigated only on pairs and was strongly correlated with the date Protection Island. The overall burrow occu- that the egg was laid. pancy, in terms of the percentage of burrows that were entered at night, increased rapidly NOCTURNAL ACTIVITY during the early part ofApril until it first peaked Patterns of circadian activity varied consid- at approximately 60 to 65% (Fig. 2). In 1975 erably among populations. On Protection and the first peak apparently occurred on 24 April, Smith islands, the first auklets landed on the and in 1976 on 23 April. In 1976,94% of the nesting areas approximately 1 to 1.5 hr after eggswere laid in burrows that were occupied sunset;while on Destruction Island, breeding during the “assembly period,” which strongly auklets began arriving after sunsetbefore their suggeststhat the breeding population arrived eggshatched and before sunset after the eggs on the island at that time. During both 1975 hatched (Fig. 3). and 1976, overall colony attendance rapidly A few hours before each evening arrival, declined after the first peak of activity and Rhinoceros Auklets assembledin rafts closeto reached its lowest level (about 20%) at the on- the island. At Protection and Destruction is- set of egg laying in early May. lands they then left the rafts either singly or in Occupancy records of individual burrows small groups,circled in front of the colony site showed that most burrows active during the several times, and then landed close to their “assembly period” were initially occupied for burrows. At Smith Island, however, there was RHINOCEROS AUIUET IN WASHINGTON 147

RHINOCEROS AUKLET FLIGHT PATTERN

m E 2000 0100 0600

FIGURE 5. Effect of bright moonlight on Rhinoceros Auklet flight schedules,Protection Island.

50 28-29 AUGUST 1976 same way as burrow occupancy rates (Fig. 2). It increased throughout the egg-laying and 2000 0100 0600 hatching periods, and peaked in early August, at the beginning of fledging. During July and early August, there was also a corresponding . arriving .SR sunrise 0 departing ss s”“sel increasein vocalization during the early morn- ing hours. This became most pronounced at FIGURE 4. Rhinoceros Auklet arrival and departure flight schedules,Protection Island. the onset of fledging, when both adults and chickscalled frequently between midnight and sunrise. no stagingand circling before the birds’ arrival on the colony. EGG-LAYING DATES Plotting the numbers of flights against time Egg laying on Protection and Destruction is- revealed peaksin both initial arrivals and final lands began between 30 April and 7 May dur- departures (Fig. 4). Since both weather and ing each year from 1974 through 1976 (Fig. location of island may influence auklet activity 6). On Smith Island, where the population was cycles, these flight patterns were only repre- less than one tenth that on the two larger is- sentative of calm nights on Protection Island. lands, egg laying was later. The egg-laying Mass arrivals characteristically began 1 to 1.5 schedulesof the different populations differed hr after sunset and lasted for approximately most notably in synchrony and frequency dis- one hr. Although birds arrived and departed tribution of laying. Frequency distributions in all night long, they tended to accumulate on egglaying were significantly different not only the nesting areas during the night. Starting among populations during the same breeding about 2 hr before sunrise, auklets began leav- season,but also within populations between ing the island in increasingnumbers, reaching breeding seasons(Table 2). Synchrony and fre- a peak between 60 and 30 min before sunrise. quency of egg laying on Protection Island in The last birds usually departed the island be- 1976 were not significantlydifferent from those tween 30 and 15 min before sunrise. on Destruction Island in 1974. Consequently, Flight activity to and from the colony sites egg laying was not always more synchronized was greatly reduced on moonlit nights (Fig. 5). in the Destruction Island population, as data Not only were there fewer flights on the moon- from 1975 suggest. lit night of 8 to 9 July than on the overcast night of 5 to 6 July, but also the arrival pattern INCUBATION was markedly different. Instead of the usual Rhinoceros Auklets incubate their single egg early peak, birds arrived throughout most of by placing it next to one of the two lateral the night, and a much less pronounced peak brood patches that are located beneath their was reached about midnight. wings. Incubation usually begins on the day Activity, as indicated by the total number the egg is laid, but sometimes eggswere not of nightly flights, fluctuated seasonally in the being incubated during the daytime for up to 148 ULRICH W. WILSON AND DAVID A. MANUWAL

Protection Island, 1975 (n = 51) mean: May 17

l-l

Jl-rllll~lln, , , 25 30 5 10 15

Protection Island, 1976 (n= 53) mean: May 22

Smith Island,1974 (n = 60) mean : May 26

Destruction Island, 1974 (n=47) mean: May 18

l-l m n nil l-l I I I I I I I I I 30 5 10 15 20 25 30 5 10 15

Destruction Island, 1975 (n = 49) mean: May 12

Ill-r- n-l-h n n n f-l l-l I I I I I 30 5 10 15 20 25 30 5 10 15 May June FIGURE 6. Rhinoceros Auklet egg-layingdates on Destruction Island, Smith Island, and Protection Island (Destruc- tion Island data from Leschner 1976). eight days. We do not know, however, if these tween 16 June and 27 July 1976. On Smith eggs were incubated during the night. This Island in 1974, hatching occurred between 20 seemingdelay in beginningincubation did not June and 15 July; eggson Destruction Island seem to affect egg viability. We believe that hatched that year between 15 June and 19 July, both sexesincubated, but we did not ascertain and between 15 June and 7 July 1975 (Lesch- the rhythm between them. Burrows with in- ner 1976). cubating birds were usually entered nightly, In order not to disturb the birds, we did not suggesting24-hr incubation shifts. On several attempt to observe the precise sequence of occasions,however, incubating birds were not events during hatching. On several occasions, relieved for up to four days during the early however, eggsthat had pip holes about one cm part of the incubation period. We also found in diameter were found during burrow checks. that a pair of auklets frequently deserted their In all cases,there was much vocalization from egg for periods lasting from 1 to 3 days. In- the adult and the chick inside the egg during cubation periods averaged 44.9 days (range 39 that time, and hatching was completed within to 52 days) on Protection Island, and 45.1 days 24 hr (n = 4). On Protection Island, the mean (range 41 to 49 days) on Destruction Island period that chicks were brooded was 3.9 days (Leschner 1976). (n = 23, R = 0 to 9, SD = 2.6).

HATCHING AND BROODING CHICK DIET Auklet eggson Protection Island hatched be- Rhinoceros Auklets feed fish to their chicks. tween 17 June and 17 July in 1975, and be- During our study, the relative importance of RHINOCEROS AUKLET IN WASHINGTON 149

TABLE 2. Chi squareanalysis of egg-layingpatterns of sandlance, herring, night smelt, and Pacific RhinocerosAuklets on Protection Island (PI), Destruction saury were also major prey species,although Island (DI) and Smith Island (SI). their relative importance varied among years. Whereas Pacific herring was important in Comparison x2 df Probability 1974, sandlanceand night smelt were the pre- PI (75): PI (76) 17.88 8 P < 0.025 dominant speciesin 1975, and rockfish were DI (74) : DI (75) 23.86 8 P < 0.005 the most important prey in 1979 to 198 1. Dur- PI (75): DI (75) 25.17 8 P < 0.005 DI (74) : SI (74) 31.28 P < 0.0005 ing 1983, El Nifio conditions persisted off the PI (76) : DI (74) 7.50 : P > 0.40 Washington coast, and water temperatures were 2 to 3°C higher than normal. At that time, Pacific saury became the major component of major prey species consistently differed be- the chick diet on Destruction Island. The di- tween the offshore Destruction Island and the verse diet of those nestlings also frequently inshore Protection and Smith islands’ popu- includedkelp greenling,popeye blacksmelt,and lations (Table 3). On the inshore islands, the immature salmon. two most important prey specieswere Pacific During our study, Protection Island auklets sandlance and Pacific herring, which com- consistently delivered heavier food loads to prised 89.4 to 96.6% of the total weight of fish their chicks than did auklets from Destruction that was delivered to chicks during the period Island (P < 0.01). The six-year average on 1974 to 1983. Pacific sandlance was always Protection Island exceededthe average on De- the predominant prey item, its relative fre- struction Island by 12.4% (Table 4). quency varying from 63.8 to 90.7%. Auklets on Protection Island infrequently delivered NESTLING GROWTH northern anchovy and immature salmonids to Of the four growth parameters we measured their chicks. (wing, culmen, tarsus lengths, and weight), In contrast, on the offshore island the single weight was the most variable (Table 5). After most important prey specieswas the northern hatching, the daily weight gain gradually in- anchovy, which varied in relative frequency creased and reached its highest average rate from26.8%in 1975 to 73%in 1981. Rockfish, between 10 and 25 days after hatching. Fol-

TABLE 3. Relative frequency in weight (%) of prey speciesdelivered to Rhinoceros Auklet nestlingsin Washington, 1974-1983.

Smith Colony site Destructmn Island Protection Island Island Yea1 1974’ 1974’ 1979 1980 1981 1983 1975 1976 1979 1980 1981 1983 1974

n (No. food loads) 2s 94 105 73 57 43 32 180 89 72 30 46 32

Prey species: Rockfish sp. 2.3 1.5 19.1 26.7 14.6 (&bastes sp.) Northern anchovy 56.0 26.8 47.9 54.3 73.0 45.1 0.8 2.1 4.1 4.7 1.3 (Engraulis mordax) Pacific sandlance 6.5 31.7 13.5 2.8 4.5 70.6 63.8 87.6 89.3 76.3 90.7 78.1 (Ammodyteshex- apterus) Herring 20.8 4.4 6.5 5.0 0.2 1.0 26.0 25.7 2.7 6.0 13.1 2.2 15.6 (Clupea harengus) Salmon sp. 2.9 3.1 0.7 2.4 6.7 4.4 3.7 2.8 5.5 (Oncorhynchussp.) Surf smelt 14.4 2.0 1.4 3.1 0.3 6.3 (Hypomesuspreti- osus) Night smelt 31.9 3.1 0.2 1.4 (Spirinchusstark@ Kelp greenling 0.7 6.4 0.2 (Hexagrammos deca- grammus) Popeye blacksmelt 3.3 0.8 (Bathylagusochoten- sis) Pacific saury 2.1 0.8 3.7 51.9 (Colobissaira) Miscellaneous 1.7 0.7 0.7 0.9 2.0 0.2 0.2 0.9 1.0

’ Data from Leschner (1976) 150 ULRICH W. WILSON AND DAVID A. MANUWAL

TABLE 4. Mean weights (g) of food loads delivered to test: P < 0.001 2 = -3.78, P < 0.07 Z = Rhinoceros Auklet chicks, Protection Island vs. Destruc- - 1.63). tion Island.* During 1974 Smith Island chicks reached 11% higher nestling weights and fledged 13% Protection Island Destruction Island heavier than did birds from Destruction Is- 1975: 32.28 (n = 32) l1974: 19.00 (n = 25) land. Similarly, in 1975 Protection Island 1976: 29.52 (n = 180) ‘1975: 31.05 (n = 94) chicks attained 4% higher peak and fledging 1979: 33.60 (n = 89) 1979: 28.20 (n = 105) 1980: 33.50 (n = 72) 1980: 28.72 (n = 73) weights. Destruction Island chicks also re- 1981: 32.05 (n = 30) 1981: 27.54 (n = 57) mained in the burrow somewhat longer than 1983: 33.92 (n = 46) 1983: 28.07 (n = 43) those from the inshore colonies. During 1979 Pooled mean: Pooled mean: to 198 1, Protection Island fledglingscontinued 31.78 (n = 449) 28.28 (n = 397) to be heavier than those on Destruction Island. *F = 8.73, P < 0.01. We measured chicks from both colonies twice ’ ’ Data from Leschner (1976). in July of each year and constructed growth curves following Ricklefs and White’s (1975) method. K values for these curves were com- lowing this, weight increasebegan to taper off, puted according to Ricklefs (1967). Compar- and chicks reached their maximum weight be- ative data were generatedand analyzed for De- tween the agesof 37 and 55 days. During our struction Island in 1974 and 1975 and for study, 85% of the chicks lost weight before Protection Island in 1975 and 1976 (Table 7). fledging, up to nine days beforehand. Protec- Ricklefs and White (1975) pointed out that the tion Island chicksfledged at approximately 75% composite growth curves obtained in this way of adult weight. The wing grew from approx- are indicative of the environment of a popu- imately 25 mm at hatching to 140 to 160 mm lation at a particular time and cannot be com- (88% of adult length) at the time of fledging. pared with curves obtained from a sample of Growth was fastest and variation greatestbe- nestlingsthat were measured throughout their tween 15 and 30 days of age. At fledging, the development period, as we had done earlier culmen was only 79% of adult length, but the (Table 6). The consistently higher asymptotes tarsus was essentially fully grown at 40 days. for the Protection Island birds compared to In 20 chicks with known hatching dates, none those on Destruction Island (F = 15.35, P = had an egg tooth on the lower mandible. The O.OOS),however, indicate that the faster growth mean time that an eggtooth persistedwas 4.4 and heavier chicks from the inshore popula- days (n = 20, R = 2 to 8, SD = 1.96). Eggteeth tion were not isolated events in 1974 and 1975, appeared to be shed rather than worn off. Be- but occur during other breedingseasons as well. cause these structures are so variable in their Auklets from inshore populations that persistence,they have little value for estimat- hatched early in the nesting seasontended to ing the age of young chicks. Growth parame- grow better than those hatched late in the ters of chicks differed markedly between the season,but this was not found in the coastal coastal and inshore populations (Tables 6 and population (Table 8). In 1976, early-hatched 7). During 1974 and 1975, chicks on the coast- auklets from Protection Island attained sig- al island reached lower peak weights and nificantly higher peak and fledgingweights than fledgedlighter than did chicksfrom the inshore did chickshatched late. Similarly, during 1974 colonies (Wilcoxon-Mann-Whitney rank-sum and 1975 early-hatched young from Smith and

TABLE 5. Development of Rhinoceros Auklet nestlings(Protection Island 1975, n = 3 l), compared with measurements of breeding adults (Protection Island 1975, n = 12).

Weight Wing length Tarsus length Culmen length 0 (mm) (mm) (mm) Age (days) Mean SD Mean SD Mean SD Mean SD Nestling appearance 1 55 (4) 24.8 (1.7) 24.6 (0.6) 15.5 Down almost black, egg-tooth present 5 79 (10) 28.1 (1.8) 27.2 (1.1) 16.4 Egg-tooth may or may not be present 10 121 (16) 33.4 (2.2) 29.3 (1.3) 18.1 Emergenceof primary remiges 15 171 (26) 45.5 (3.3) 32.1 (1.5) 19.8 20 215 (37) 63.8 (7.6) 34.1 (1.6) 21.2 Down becomes paler 25 263 (42) 84.0 (8.5) 35.7 (1.6) 22.3 301 (45) 104.0 (8.3) 36.7 (1.6) 23.2 Loss of down around face :: 329 (50) 114.0 (7.3) 37.4 (1.4) 24.2 Loss of down on wings and back 40 346 (49) 131.1 (6.7) 37.7 (1.4) 25.2 Loss of down on breast and belly 45 360 (47) 142.8 (4.2) 37.9 (1.3) 26.0 Small down patchesmay remain on rump and neck Adult 545 (38) 189.2 (5.5) 38.2 (1.1) 33.3 (2.8) RHINOCEROS AUKLET IN WASHINGTON 151

TABLE 6. Comparisonsof complete growth parametersof RhinocerosAuklet chicksweighed daily from Destruction, Protection, and Smith islands, Washington.

M.SXl Mean peak MeaIl Mean daily No. chicks hatching chick weight fledging Mean nestling weightgain Locationand year measured weight (9) (9) weight (g) period(days) (g/day) !? a’ Destruction Island’ 1974 19 51 331 308 54.3 4.73 0.064 338 1975 37 52 357 343 51.0 5.71 0.067 385 Smith Island 1974 17 54 372 356 48.3 6.25 0.056 390 Protection Island 1975 31 55 371 358 49.3 6.15 0.065 400 1976 40 53 369 353 50.6 5.93 0.071 398

’ Data from Leschner(1976). 1 k = growthconstant (Ricklefs 1967). 3a = asymptote.

Protection islands, respectively, reached sig- maneuverability may be important in avoid- nificantly higher peak weights than did late- ing large obstacles,and the occasionalattempt hatched chicks, but their fledging weights did by Glaucous-winged (Larus glaucescens)or not differ significantly (P > 0.10). On Destruc- Western (L. occidentalis)gulls to steal fish that tion Island, we found no evidence of such re- are being taken to auklet chicks. Although lationships. kleptoparasitism occurs at Rhinoceros Auklet colonies, it does not appear to be as significant BREEDING SUCCESS to the breeding successas it is with the Atlantic The reproductive successof Rhinoceros Auk- Puffin (F. arctica)in eastern Canada (Nettle- lets in Washington varied between populations ship 1972). Very little kleptoparasitism of and years (Table 9). In 1975 hatching success Tufted and Horned (F. corniculata)puffins was and fledgingsuccess were higher on Protection noted in the Barren Islands, Alaska (Manuwal Island than on Destruction Island. Auklets and Boersma 1977) and none was mentioned from Destruction Island also reproduced bet- by Wehle (1983) for other Alaskan colonies. ter in 1975 than they did in 1974, and Pro- The colony attendancepattern of auklets ap- tection Island birds had better successin 1976 pears to be typical for a seasonally breeding than in 1975. During the three years for which sea bird at northern latitudes. The pre-laying we have detailed data, overall successwas ap- exodus which we found has been well docu- parently higher on Protection Island than on mented for procellariiforms (Harris 1969) but Destruction Island (Table 9). not in alcids. Data that suggesta pre-laying Causes of chick mortality are not entirely exodus have been reported for Tufted Puffins known, but the adult auklets may have been (Amaral 1977, Wehle 1983) and for Ancient a major factor. Leschner (1976) found that sev- Mm-relets (Synthliboramphusantiquus; Sealy eral of the dead chicks on Destruction Island 1975). This absenceperiod appearsto be nec- died from peck wounds to the head; some of essaryfor females to store sufficient energy re- these chicks may have wandered from their servesfor eggformation (Ashmole 196 3, 197 1; own burrows and entered another burrow Lack 1966, 1967; Harris 1969; Perrins 1970). where they were killed by the adults. Predation This would allow them to exploit distant fish- appeared to be unimportant during the time of our study. A few auklets on Protection Is- land were killed by Great Horned Owls (B&o TABLE 7. Comparisonsof compositegrowth parameters virginianus),and a few others died by flying of Rhinoceros Auklet chicks, Destruction Island vs. Pro- into man-made objects. tection Island, 1974 to 1981.

DISCUSSION DestructionIsland ProtectionIsland As with Tufted Puffins, Fratercula cirrhata Year k a n k a n (Amaral 1977, Wehle 198 3) Rhinoceros Auk- 1981 0.049 412 18 0.06 1 440 18 lets nest primarily on sea-facing slopes or on 1980 0.049 394 17 0.078 430 22 level areas adjacent to the edge of islands. The 1979 0.058 400 18 0.076 432 19 slopedareas, in particular, allow the birds easy 1976 0.07 1 432 20 1975 0.068 395 19 0.076 412 20 accessto burrows; by flying upslope during 1974 0.074 335 19 their approach, the birds can reduce air speed All valuescomputed from compositegrowth curves constructed according and make a softer, coordinated landing. Such to Ricklefsand White (1975). Chickswere weighed twice in July. 152 ULRICH W. WILSON AND DAVID A. MANUWAL

TABLE 8. Growth comparisonsbetween early- and late-hatched Rhinoceros Auklet chicks in Washington.

Destruction Island’ Smith Island Protectmn Island 1974 1975 I974 1975 1916 MG3Il SD MeaIl SD MeaIl SD MeaIl SD M.%Xl SD

Peak weight Early hatch 337 (18.3) 366 (24.5) 380 (27.0)** 380 (26.7)* Late hatch 301 (55.5) 362 (24.6) 341 (57.6)** 359 (22.6)* Fledging weight Early hatch 319 (15.8) 362 (22.9) 368 (28.9) 368 (26.9)* Late hatch 283 (56.3) 341 (27.0) 334 (60.5) 343 (28.5)* Nestling period Early hatch 50.0 (3.0) 51.3 50.3 50.3 (3.1) Late hatch 50.5 (2.1) 51.6 48.6 49.5 (2.1) Sample size Early hatch 6 10 9 12 Late hatch 6 10 10 13

Comparisons are based on sub-samples of samples in Table 6 (first hatched third vs. last hatched third). *P < 0.05 Wilcoxon-Mann-Whitney rank sum test. ** P < 0.10 Wilcoxon-Mann-Whitnev rank sum test. ’ Data from Leschner (1976). 1

ing areas that may be more productive than Differences in egg-laying synchrony found waters near the colony site. among populations and years have been at- Colony visitation patternsamong the puffins tributed in other speciesto differences in food show some interesting variability. The Tufted availability (Lack 1966, Veen 1977, Manuwal and Horned puffins are typically diurnal, 1979), to social factors (Darling 1938, Burger whereasthe Rhinoceros Auklet is usually noc- 1979, Gochfeld 1979), or to age composition turnal. Visitation patterns of auklets vary, (Coulson and White 1958; see Gochfeld 1980 however, among colonies: nocturnal or cre- for a review). Our information suggeststhat puscular-Protection and Smith islands (this food availability is the most plausible expla- study), British Columbia (Summers and Drent nation for the local and yearly variations we 1979, Vermeer 1979), and Alaska (Manuwal found in egg laying in auklets. This view is and Boersma 1977); both nocturnal and cre- reinforced by the substantialdifferences in di- puscular, depending on the stageof the repro- etary composition between the coastal and in- ductive cycle-Destruction Island (Leschner shore colonies. 1976); and diurnal- Williamson Rocks, Our data, as well as those of others (Man- Washington (Thoresen 1980) Oregon (Scott et uwal and Boersma 1977; Vermeer 1979, 1980; al. 1974), California (Ainley and Lewis 1974) Hatch 1984) indicate that prey speciesbrought and Japan (Thoresen 1983). One explanation to nestling Rhinoceros Auklets may show sub- for noctumality is that it evolved as a way to stantial intercolonial, annual, and latitudinal avoid predation and kleptoparasitism (Lack variation. The striking difference between the 1966, Cody 1973). A thorough analysis of ac- diets of coastal and inshore populations may tual and potential predators around various well reflect differences in the physical and bi- Rhinoceros Auklet colony sites might clarify ological marine environments of the two areas. this interpretation. Alternatively, the noctur- Waters of Puget Sound and the Strait of Juan nal habit may be a partly learned behavior that de Fuca are characterized by much tidal mix- persists where it is traditional. Evidence to ing (Long 1983). This effect is so strong that support this view is that three of the four diur- primary producers do not remain in the eu- nal populations are small, new, or recently re- photic zone long enough for extensive, dense colonized. A third possibleexplanation is that plankton blooms to occur. Off the coast, by visitation times are related to food availability contrast,coastal upwelling injects nutrient-rich (Ashmole 197 1, Vermeer 1979). Since diurnal, waters into the euphotic zone, which is much vertical migration habits differ among species more stratified during the summer. Extensive, of marine organisms,Rhinoceros Auklet pop- denseplankton blooms are possiblein this nu- ulations that exploit different prey speciesmay trient-limited system. This probably explains capture food for their chicks at different times. why the filter-feeding northern anchovies were The time of prey availability, as well as the more common in the diets of chicks on De- distance from colonies to the birds’ fishing struction Island than of chicks on Protection grounds,may also influence the auklets’ initial Island. Coastal upwelling, however, is a result arrival time. ofprevailing winds. Since winds are asvariable RHINOCEROS AUKLET IN WASHINGTON 153

TABLE 9. Reproductive successof Rhinoceros Auklets on Destruction Island, 1974-1975, and Protection Island, 1975-1976.

Destruction Island1 Protection Island Attribute (all in percent) 1974 1975 1975 1976

Excavated burrows that had 70 (n = 99) 79 (n = 107) 65 (n = 82) 62 (n = 80) eggslaid in them Excavated burrows with 20 (n = 99) 26 (n = 107) 34 (n = 82) 39 (n = 80) hatched eggs Undisturbed burrows with 53 (n = 64) 59 (n = 121) 53 (n = 150) 57 (n = 137) chicks Egg desertion owing to nest 33 33 19 18 checksduring incubation Hatching success 76 75 82 92 Nestling mortality 26 (n = 19) 16 (n = 37) 7 (n = 31) 3 (n = 46) Pledgingsuccess per chick hatched 74 93 97 Pled&a successper eaa laid 56 76 89

Calculations: D = C - B, E = C/A, G = 100 - F, H = G x E/l00 ’ ’ Data from Leschner (1976). as prevailing weather conditions, considerable ents (Hedgren and Linnman 1979, Vermeer fluctuations in the coastal system can be ex- and Cullen 1982). Furthermore, differential pected. The inshore water system, less influ- growth between early- and late-hatched young enced by weather and major offshore shifts in has been attributed to age and breeding ex- currents, is more stable, as shown by the 1983 perience of adults (Coulson 1966, Coulson and breeding season.El NiLToconditions in 1983 White 1958) and to socialfactors (Hedgren and apparently forced Destruction Island auklets Linnman 1979). We found differential growth to switch their diet to Pacific saury, whereas in the inshore population on Protection Island those on Protection Island maintained their but not on the coastal island. Intuitively, it normal diet of sandlance. Differences in the would seem to make more senseto see differ- nature and stability of the marine environment encesin growth between early and late hatch- of these two auklet populations appear to ex- ers on Destruction Island, where auklets feed plain differencesin their diets. Unfortunately, their chicks on a much less predictable food Rhinoceros Auklet prey specieshave not been supplyand deliver smaller feedsto their chicks, adequately sampled in either the Strait of Juan and where young peak and fledge lighter than de Fuca or on the outer coast, so data on prey auklets nesting in the Strait of Juan de Fuca. availability cannot be compared directly. Again, the interactions between the birds and Presumably, changesin oceanographiccon- their prey probably are somehow involved in ditions also account for annual differences in these observed differences in growth patterns. prey-species composition and abundance. Breeding successof Washington auklets falls When normal prey become scarce, sea birds within the rangesof puffin populations in Brit- switch to other prey. In our study, auklets re- ish Columbia (Vermeer 1979, 1980) and in spondedto the El Niffo effect in 1983 depend- Alaska (Wehle 1983; Manuwal, unpubl.). Rates ing on their location as indicated above. Ver- of hatching and fledging successwere lower in meer (1978, 1980) found that changes in the coastalcolony than in the inshore colonies. oceanographicconditions apparently resulted Bad weather (e.g.,precipitation or strongwinds) in a reproductive failure in northern British can affect birds at the colony and at sea (Net- Columbia in 1976. Rhinoceros Auklets there tleship 1972, Dunn 1973, Birkhead 1976). This switched to an alternate prey, Pacific saury, probably occurred at our study sites. Leschner compared with the normal sandlance and (1976) found that burrows on Destruction Is- rockfish. land were frequently flooded by heavy rains, The three speciesof puffins in Alaska all rely but those on Protection and Smith islandsnev- heavily on capelin as the primary prey, and on er became flooded during our study. Flooding sandlanceas the secondaryprey species(Wehle of burrows may well disrupt or even terminate 1983). Capelin has not been found in auklet incubation and may also force chicks to leave diets south of southeastern Alaska. Overall, the safetyoftheir nests.Nettleship (1972) found the sandlance is the predominant species in that breeding successof Atlantic Puffins during nestling diets of all three puffins from Alaska an extremely wet summer was approximately to Washington. 50% lower than during a normal year. The fact Chick growth rates are sensitive to the types that Protection and Smith islands lie in the and quantities of prey that are brought by par- rain shadow of the Olympic Mountains may 154 ULRICH W. WILSON AND DAVID A. MANUWAL contribute to the higher breeding successof on the breeding biology of the Kittiwake Rissa tri- their auklet populations. Rough seasmay also ductylu. Ibis 100:40-5 1. DARLING,F. F. 1938. Bird flocksand the breeding cycle. interfere with the ability of seabirds to capture Cambridge Univ. Press, Cambridge, England. prey. The more sheltered inland waters may DUNN, E. 1973. Changes in fishing ability of terns as- afford better fishing conditions for the auklets sociatedwith windspeed and sea surface conditions. during periods of heavy weather. Nature (Lond.) 224:520-52 1. GOCHF~LD,M. 1979. Breedingsynchrony in Black Skim- CONCLUSIONS mers: colony vs. subcolonies.Proc. Colonial Water- bird Group 2:171-177. With the exception of its nocturnality at most GOCHFELD,M. 1980. Mechanisms and adaptive value colonies, the breeding biology of the Rhinoc- of reproductivesynchrony in colonial seabirds,p. 207- eros Auklet is nearly identical to that reported 270. In J. Burger, B. Olla, and H. Winn [eds.], Be- havior of marine animals, Vol. 4: Marine birds. Ple- for the Tufted and Horned puffins, with which num Press, New York. it is sympatric in a few locations in northern HARRIS,M. P. 1969. Food as a factor controlling the British Columbia and Alaska. A more com- breeding of Puffinuslherminieri. Ibis 111:139-l 56. plete understandingof the biology of thesepuf- HART, J. 1973. Pacific fishesof Canada. Bull. Fish. Res. fins is possiblewith future detailed studies on Board Can. 180. HATCH, S. A. 1984. Nestling diet and feeding rates of behavior and on availability, distribution, and Rhinoceros Auklets in Alaska. In D. Nettleship, G. natural history of major prey species. Sanger, and P. Springer [eds.], Marine birds: their feeding ecology and commercial fisheries relation- ships. Can. Wildl. Serv. Spec. Publ. ACKNOWLEDGMENTS HEDGREN,S., ANDA. LINNMAN. 1979. Growth of Guil- We owe specialthanks to L. Leschnerfor making her data lemot Uria aalge chicks in relation to times of hatch- from Destruction Island available to us and for assisting ing. Omis Stand. 10:29-36. in various phases of data collection. We also thank N. LACK, D. 1966. Population studies of birds. Clarendon Thomas, K. Vermeer, and D. Wehle for critically review- Press, Oxford, England. ing this manuscript.We are grateful for the logisticsupport LACK, D. 1967. Interrelationships in breeding adapta- provided by the 13th U.S. Coast Guard District during tions as shown by marine birds. Proc. XIV Int. Or- work on Destruction Island and Smith Island. Financial nithol. Congr. (1966):3-42. supportin 1974 to 1976 was partly provided by a National LESCHNER,L. L. 1976. The breeding biology of the Rhi- Wildlife Federation Post-doctoral Fellowship to D. Man- noceros Auklet on Destruction Island. MScthesis.. uwal and a contract from the Nongame Program of the Univ. of Washington, Seattle. Washington Department of Game. Additional support LONG, E. R. [ed.] 1983. A synthesis of biological data came as a grant from the National Audubon Societyto D. from the Strait of Juan de Fuca and northern Puget Manuwal. Our thanks for their assistanceduring the field Sound. U.S. Environ. Prot. Agency, Interagency En- seasongo to L. Cornelius, E. Cummins, C. Dietrich, D. ergy Environment R and D Program Rep. EPA-600I Fitzner, L. Harmon, N. Manuwal, J. Matthews, and D. 7-82-004. Wilson. We are also indebted to A. Rohweder for the use MANUWAL,D. A. 1974. The natural history of Cassin’s of her cabin on Protection Island and to J. Goodson for Auklet (Ptychoramphusaleuticus). Condor 76:421- typing the original manuscript.Finally, we thank our wives 431. for putting up with our long periods of absencefrom our MANUWAL,D. A. 1979. Reproductive commitment and families. successof Cassin’s Auklet. Condor 8 1:11 l-l 2 1. MANUWAL.D.. AND D. BOERSMA.1977. Dvnamics of marine bird populationson the Barren Islands, Alas- LITERATURE CITED ka, p. 294-420. In Environmental assessmentof the Alaskan continental shelf. Annual reports of principal AINLEY, D. G., AND T. J. LEWIS. 1974. The history of investigators,Vol. 4. NOAA Environmental Research Farallon Island marine bird populations, 1854-l 972. Laboratory, Boulder, CO. Condor 76432-446. NETTLESHIP,D. 1972. Breeding successof the Common AMARAL,M. J. 1977. A comparative biology of the Tuft- Puffin (Fratercula arctica L.) on different habitats at ed and Homed puffins on the Barren Islands, Alaska. Great Island, Newfoundland. Ecol. Monogr. 42:239- M.Sc.thesis., Univ. of Washington, Seattle. 268. ASHMOLE,N. P. 1963. The regulation of numbers of PERRINS,C. M. 1970. The timing of birds’ breeding sea- tropical oceanic birds. Ibis 103:458-473. sons. Ibis 112:242-255. ASHMOLE,N. P. 1971. Seabird ecology and the marine RICHARDSON,F. 1961. Breeding biology of the Rhinoc- environment. In D. S. Famer and J. R. King [eds.], eros Auklet on Protection Island, Washington. Con- Avian Biology, Vol. 1. Academic Press, New York. dor 631456-473. BIRKHEAD,T. R. 1976. Effectsof sea conditions on rates RICKLEFS,R. E. 1967. A graphicalmethod of fitting equa- at which Guillemots feed chicks. Br. Birds 69:490- tions to growth curves. Ecology 48:978-983. 492. RICKLEFS,R. E., AND S. C. WHITE. 1975. A method for BURGER,J. 1979. Colony size: a test for breeding syn- constructingnestling growth curves from brief visits chrony in Herring Gull (Larus urgent&us) colonies. to seabird colonies. Bird-Banding 46: 135-l 40. Auk 96:694-703. SCOTT, J. M., W. HOFFMAN,D. AINLEY,AND C. F. ZEIL- CODY, M. L. 1973. Coexistence, coevolution and con- LEMAKER.1974. Range expansion and activity pat- vergent evolution in seabird communities. Ecology terns in Rhinoceros Auklets. West. Birds 5: 13-20. 54:31-44. SEALY,S. G. 1975. Feeding ecology of the Ancient and COULSON,J. C. 1966. The influence of the pair-bond and Marbled murrelets near Lanaara Island. Can. .I. Zool. age on the breeding biology of the Kittiwake Gull 53:418-433. Rissa tridactyla. J. Anim. Ecol. 35:269-279. STORER,R. W. 1945. Structuralmodifications in the hind COULSON,J. C., AND E. WHITE. 1958. The effect of age limb in the Alcidae. Ibis 87:433-456. RHINOCEROS AUKLET IN WASHINGTON 155

SUMMERS,K. R., AND R. H. DRENT. 1979. Breeding bi- VERMEER,K. 1979. Nesting requirements, food and ology and twinning experiments of Rhinoceros Auk- breeding distribution of Rhinoceros Auklets, Cero- lets on Cleland Island, British Columbia. Murrelet 60: rhinca monocerata, and Tufted Puffins, Lunda cir- 16-22. rhata. Ardea 67:101-l 10. THORESEN,A. C. 1980. Diurnal land visitations by Rhi- VERMEER,K. 1980. The importance of timing and type nocerosAuklets. West. Birds 11:154. of prey to reproductive successof Rhinocer& Aukjets THORESEN,A. C. 1983. Diurnal activity and social dis- Cerorhincamonocerata. Ibis 122:342-350. plays of Rhinoceros Auklets on Teuri Island, Japan. VERMEER,K., ANDL. CULLEN. 1982. Growth comparison Condor 85:373-375. of a plankton- and fish-feedingalcid. Murrelet 63:34- VEEN, J. 1977. Functional and causal aspects of nest 39. distribution in coloniesof the SandwichTern (Sterna WEHLE,D. H. 1983. The food, feeding, and development sandvicensisLath.). Behaviour Suppl. 20: 1-193. of young Tufted and Homed puffins in Alaska. Con- VERMEER,K. 1978. Extensive reproductive failure of dor 85:427-442. RhinocerosAuklets and Tufted Puffins. Ibis 120:112.