De Santo and Nelson 



Chapter 3 



Reproductive Ecology of Auks 



Table I Extant members of the family Alcidae 



Common name(s) 



Scientific name 8 



Dovekie (Little Auk) Alle alle 



Razorbill (Razorbill Auk) Alca torda 



Common Murre (Common Guillemot) Uria aalge 



Thick-billed Murre (Brunnich's Guillemot) Uria lomvia 



Black Guillemot Cepphus grylle 



Spectacled Guillemot (Sooty Guillemot) Cepphus carbo 



Pigeon Guillemot Cepphus columba 



Marbled Murrelet Brachyramphus marmoratus 



Kittlitz's Murrelet Brachyramphus brevirostris 



Xantus' Murrelet Synthliboramphus hypoleucus 



Craveri's Murrelet Synthliboramphus craven 



Ancient Murrelet Synthliboramphus antiquus 



Japanese Murrelet (Crested Murrelet) Synthliboramphus wumizusume 



Crested Auklet Aethia cristatella 



Least Auklet Aethia pusilla 



Whiskered Auklet Aethia pygmaea 



Cassin's Auklet Ptychoramphus aleuticus 



Parakeet Auklet Cyclorrhynchus psittacula 



Rhinoceros Auklet (Horn-billed Puffin) Cerorhinca monocerata 



Tufted Puffin Fratercula cirrhata 



Horned Puffin Fratercula comiculata 



Atlantic Puffin Fratercula arctica 



"Nomenclature according to American Ornithologists' Union (1983) 



abandoned burrows, on covered ledges, or in self-excavated 

 holes (Ewins and others 1993; Harris and Birkhead 1985). 

 Nests of Dovekies are found most often in cracks in cliffs 

 and among boulders (Harris and Birkhead 1985). Parakeet, 

 Crested, Whiskered, and Least auklets nest under rocks in 

 talus fields, whereas Cassin's Auklets excavate burrows in 

 the soil (Springer and others 1993). The Synthliboramphus 

 murrelets (Xantus', Craveri's, Ancient, and Japanese) nest 

 in existing holes and hollows around tree roots, logs, or 

 under rocks, or in crevices. Additionally, Japanese and Ancient 

 murrelets may nest in self-excavated holes (Springer and 

 others 1993). Kittlitz's Murrelets nest in the open on rocky 

 ground. Marbled Murrelets nest in the open on rocky ground 

 in the northern part of their range. In the southern part of 

 their range, they nest on the large limbs of old-growth 

 coniferous trees in forests up to 40 km from the ocean 

 (Hamer and Nelson, this volume b; Marshall 1988a). 



Alcids are highly social birds, and most species are 

 colonial in their nesting habits (table 2). Nineteen of the 22 

 species can be found nesting in colonies consisting of 10 to 

 several thousand pairs. Craveri's Murrelets probably nest in 

 loose aggregations and as scattered pairs. The Kittlitz's 

 Murrelet is the only species considered to be truly non- 

 colonial (i.e., nesting only as isolated pairs). 



Marbled Murrelets have been described as solitary 

 (Gaston 1985) and loosely colonial (Divoky and Horton, this 



volume), and may nest solitarily in some areas, but in loose 

 aggregations in others. Simons (1980) reported a ground 

 nest that appeared to be a solitary nest. There is also strong 

 indirect evidence that murrelets nest in loose aggregations. 

 In Washington and Oregon, two concurrently active nests 

 were located 100 and 30 m apart, respectively, within a 

 forest stand (Hamer and Cummins 1991 ; Nelson, pers. obs.). 

 In addition, in Oregon, multiple nests have been found in 

 each of three trees located in different stands, and four trees 

 within a small area (40-m radius) were found to contain 

 nests (Nelson and others 1994). It is not known, however, if 

 these nests were active concurrently. 



Breeding Site, Nest Site, and Mate Fidelity 



Studies of individually marked birds have provided 

 information on the degree of breeding site and mate fidelity 

 exhibited by alcids. Strong breeding site fidelity has been 

 documented in the 15 species of alcids for which this aspect 

 of reproductive ecology has been adequately investigated 

 (Divoky and Horton, this volume) (table 2). For example, 96 

 percent of Common Murres at one colony returned to breed 

 at the same colony site the following year, and 90 percent 

 used the same nest site (Birkhead 1976 as cited by Hudson 

 1985). Similarly, Ashcroft (1979) as cited by Harris and 

 Birkhead (1985) reported that 92 percent of Atlantic Puffins 



34 



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



