Fig. 5. Differential average arrival on breeding grounds and average duration of prenesting period of thick-billed murres (Uria lomvia) and black-legged kittiwakes on various colonies in the Barents Sea. From Belopol'skii (1961). Length of prenesting period in days (shaded bars) indicated on right. Letters represent locations as follows: A = Novaya Zemlya, Kara Straits; B = Novaya Zemlya, Karmakuly Bay; C = Franz Josef Land; and D = East Murman.
Prenesting Activities
Some species are apparently able to delay maturity of sexual organs until environmental conditions are suitable for nesting—e.g., burrow and crevice nesters in the Barents Sea do not become sexually mature until snowmelt (Belopol'skii 1961). Many others, however, reach sexual maturity soon after arrival on the breeding grounds, and a few (such as jaegers and kittiwakes) mature in migration or on the wintering grounds (Belopol'skii 1961). Northern phalaropes (Lobipes lobatus) sometimes lay eggs as early as 1 week after arrival (Hilden and Vuolanto 1972). This factor, in combination with timing of arrival, affects the amount of time spent in prenesting activities (Fig. 6). Most species gain weight during this period (Belopol'skii 1961), and the time required for each species to reach full breeding condition must also depend on feeding conditions and the state of the bird on its arrival at the nesting site. These factors help explain why early arriving species are not necessarily early nesters (Fig. 6).
Fig. 6. Variation in timing of events in the reproductive cycle of Barents Sea seabirds nesting on the same island. Data from Belopol'skii (1961). Shaded bars at left indicate the prelaying periods, open bars the incubation periods, and shaded bars at right the portion of the growth period in which the chick remains at the nest site. Total length of time indicated is about 6 months.
Aside from nest building, most prenesting activity consists of courtship and territorial behavior. These activities have been well described for representative seabird species, but because assessments of time and energy devoted to them have been almost completely neglected, they are not discussed further here. For examples, see accounts in Gross (1935) for Leach's storm-petrel; Tinbergen (1935), Bengtson (1968), Höhn (1971), and Howe (1975) for phalaropes; Storer (1952) for common murre, Uria aalge, and black guillemot, Cepphus grylle; Tschanz (1959) for common murre; Brown et al. (1967) for Sabine's gull; Tinbergen (1960) for herring gull; McKinney (1961) for eiders; Snow (1963) for shag; Thoresen (1964) for Cassin's auklet; Vermeer (1963) and James-Veitch and Booth (1974) for glaucous-winged gull (Larus glaucescens); and Andersson (1973) for jaegers.
Nest Building
Although many northern seabirds have essentially no nest, they may spend considerable time working or displaying at the site (Belopol'skii 1961). Black-legged kittiwakes (Rissa tridactyla) have substantial nests, but they are built in a comparatively short time (about a week) soon after the birds arrive (Fig. 6). Shags also have substantial nests, but they are not completed until about 1 or 2 weeks before the first egg is laid (Snow 1963). Herring gulls build smaller nests, 5 to 10 days before laying, although in the Far North they and glaucous gulls may not start building the nest until the first egg is laid (Belopol'skii 1961). The eider always begins preparing the nest when the first egg is laid (Belopol'skii 1961; Schamel 1974), and terns and skuas, which build no nests, choose their sites at that time. Murres, which frequently lay their eggs directly on snow, choose a site somewhat earlier and spend considerable time protecting it (Belopol'skii 1961). Burrows may be dug within a period as short as 3 days for Leach's storm-petrel (Gross 1935) to one as long as several weeks in Cassin's auklets (Manuwal 1974a). Overall, the prelaying period is longer for burrow nesters than for those using crevices (Sealy 1973a).
The amount of time and energy spent by the male and female in nest building differs among species. In Leach's storm-petrel, the male digs the burrow (Gross 1935), whereas in eiders, the nest is built entirely by the female. In most seabird species, the sexes share in nest construction, but roles may still be separated. For example, in shags the male collects the nest material and the female builds the nest (Snow 1963).