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for insects (Cannings et al. 1987) and use their bills to
flip over cow-dung piles to probe underneath (King
1978). On the breeding grounds, they forage singly,
in pairs, and in groups (3 to 14 birds), with groups
most often occurring in habitats with high grasshopper
(Orthoptera) densities (King 1978, Jenni et al. 1981).
Groups of curlews may forage “cooperatively,” as
foragers move in the same direction, either side by side
(abreast) or in a line (King 1978). On non-breeding
areas, curlews feed by using pecks, burrow probes, and
pause-probes (Stenzel et al. 1976). Pecking is used to
capture prey on mudflat surfaces, and burrow probing
is used to capture burrowing prey such as mud crabs
(Hemigrapsus oregonensis) or burrow-dwelling trap-
door spiders (Antrodiaetidae) and decapods (Abbott
1944). Pause-probes are used primarily in submerged
habitat and involve standing motionless for 5 to 10 sec,
holding the bill partially submerged and slightly agape,
and then suddenly lurching to capture prey.
On the breeding grounds, curlews appear
to be opportunistic foragers, supplementing a diet
of invertebrates, such as grasshoppers and beetles
(Coleoptera), with small vertebrates like bird eggs
(Sadler and Maher 1976) and nestlings (Timken 1969,
Sadler and Maher 1976, Goater and Bush 1986).
On tidal estuaries, the diet of non-breeding birds
consists mostly of large, burrow-dwelling mud crab
(Hemigrapsus oregonensis) , ghost shrimp (Callianassa
californiensis), and mud shrimp (Upogebia pugettensis).
Significant numbers of bivalves less than 3 cm, marine
worms (polychaetes) 5 to 45 cm, and fish under 6 cm are
also taken (Stenzel et al. 1976, Boland 1988, Leeman et
al. 2001). Earthworms are an important part of the diet
in wet coastal pastures (Leeman 2000).
In southeastern Colorado, 55 percent of the
foraging observations occurred in shortgrass prairie
and 40 percent in crop fields (King 1978). Curlews
used cheatgrass and freshly mowed alfalfa in Oregon
(Pampush and Anthony 1993), and they foraged
predominantly in grassland in Idaho (Jenni et al. 1981).
Breeders may establish separate feeding territories in
large meadows adjacent to nesting territories Bicak
(1977). On wintering areas, curlews prefer firm mud
substrate or high-tidal areas to soft mud, sand, or low-
tidal areas (Gerstenberg 1979, Boland 1988, Engilis
et al. 1998). Foraging activities are directly related to
burrow density of prey (Stenzel et al. 1976). Curlews
probe deeper than other species of wintering shorebirds;
probe depth is consistent with data on vertical prey
distribution within sediments (Boland 1988).
Breeding biology
Phenology of courtship and breeding
Long-billed curlews arrive on breeding areas
in small groups (Jenni et al. 1981) from mid- to late
March (Oregon, Washington, Colorado, Utah, Idaho) to
mid- to late April (Wyoming, Saskatchewan, Alberta)
(Dugger and Dugger 2002). Some males and females
may arrive paired (Wolfe 1931, Forsythe 1970, Allen
1980), but both paired and unpaired males quickly
establish territories after arrival (Allen 1980, Jenni et al.
1981, Pampush 1981). Conspicuous courtship behavior
begins immediately and continues for 3 to 4 weeks,
through mid- to late April in Idaho (Jenni et al. 1981)
and Colorado (King 1978). In Oregon, aerial displays
by unpaired males occur through June (12 to 14 weeks
after arrival; Pampush 1981).
Nest building begins within one week of pairing
(Jenni et al. 1981). Nests are initiated in most areas from
early April through May. Median clutch-completion
dates for 3 years in Idaho were 14, 19, and 24 April
(Redmond 1986), and in British Columbia, 56 percent
of nests were initiated between 9 May and 31 May (n
= 50; Campbell et al. 1990). Late egg-laying dates
include the end of May in Colorado and Utah, 4 June in
British Columbia (Campbell et al. 1990), and early July
in Saskatchewan and Idaho. Laying one 4-egg clutch
took 6 days in Colorado (Graul 1971) and 5 to 7 days in
Idaho (Jenni et al. 1981). In a single nest in southeastern
Washington, Allen (1980) measured 47 hours and 25
minutes between laying of the first and second eggs.
Hatching dates range from 1 May (Oregon) to 12 July
(Wyoming) (Dugger and Dugger 2002).
Curlew chicks fledge at 38 to 45 days after
hatching (King 1978, Allen 1980, Redmond and
Jenni 1986). Females often leave brood care to
males 1 to 3 weeks after the eggs hatch (King 1978,
Allen 1980, Jenni et al. 1981). Fledged juveniles
were observed in western Idaho by mid-June and as
early as 5 July in Saskatchewan (Renaud 1980). A
flightless juvenile was seen as late as 5 August in
Saskatchewan (Maher 1973).
Courtship and breeding behavior
Long-billed curlews are monogamous and
predominantly solitary (Dugger and Dugger 2002).
After arriving on the breeding grounds, individuals
quickly disperse to establish territories in suitable