Laserfiche WebLink
<br />Life Historv <br /> <br />Breedinlz Behavior: Interior, least terns spend about 4-5 months at <br />their breeding sites. They arri~e at breeding areas from late April to <br />early June (Faanes 1983, Hardy 11957, U. S. Fish and Wildlife Service <br />1987a, Wilson 1984, Wycoff 1960, ~oungworth 1930). Courtship behavior of <br />least terns is similar throughout North America. Courtship occurs at the <br />nesting site or at some distance from the nest site (Tomkins 1959). It <br />includes the fish flight, an 'aerial display involving pursuit and <br />maneuvers culminating in a fish transfer on the ground between two <br />displaying birds. Other courtship behaviors include nest scraping, <br />copulation and a variety of postutes, and vocalizations (Ducey 1981, Hardy <br />1957, Wolk 1974). ' <br /> <br />The nest is a shallow and inqonspicuous depression in an open, sandy <br />area, gravelly patch, or exposeq flat. Small stones, twigs, pieces of <br />wood and debris usually lie near 1 the nest. Least terns nest in colonies <br />or terneries, and nests can be as close as just a few meters apart or <br />widely scattered up to hundreds of meters (Ducey 1988, Anderson' 1983, <br />Hardy 1957, Kirsch 1990, Smith and Renken 1990, Stiles 1939). The benefit <br />of semi-colonial nesting in least terns may be related to anti-predator <br />behavior and social facilitation I (Burger 1988). <br /> <br />Interior least tern eggs ar~ pale to olive buff and speckled or <br />streaked with dark purplish-brown\ chocolate, or blue-grey markings (Hardy <br />1957, Whitman 1988). Occasionally, eggs are pink instead of pale to olive <br />buff (P. Mayer and M. Schwalbach, personal communication), The birds <br />usually lay two or three eggs (Anderson 1983, ,Faanes 1983, Hardy 1957, <br />Kirsch 1987-89, Sweet 1985, Smith 1985). The average clutch size for <br />interior least terns nesting on the Mississippi River during 1986-1989 was <br />2.4 eggs (Smith and Renken 1990)1. Egg-laying begins by late May. Both <br />I <br />sexes share incubation which generally lasts 20-25 days but has ranged <br />from 17 to 28 days (Faanes 1983, >>ardy 1957, Moser 1940, Schwalbach 1988, <br />G.R. Lingle, personal communicat~on). <br /> <br />The precocial behavior of interior least tern chicks is similar to that <br />of other least terns. They hatch within one day of each other, are <br />brooded for about one week, and usually remain within the nesting <br />territory but as they mature, wander further. Fledging occurs after three <br />weeks, although parental attenti~n continues until migration (Hardy 1957, <br />Massey 1972, 1974; Tomkins 1959).1 Departure from colonies by both adults <br />and fledglings varies but is us*ally complete by early September (Bent <br />1921, Hardy 1957, Stiles 1939). iThompson (1982) presented the following <br />longevity data for coastal leas.t: terns revealed by band recoveries: <br />Percentage of Recoveries <br />Age (vears) Known and Assumed Dead (N) <br />0-5 74 percent (58) <br />5-10 9 percent (7) <br />10-15 10 percent (8) <br />15-20 4 percent (3) <br />>20 3 percent <br /> <br />12 <br />