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<br />I. INTRODUCTION
<br />
<br />The interior population of the least tern (Sterna antillarum)
<br />(hereafter referred to as the interior least tern) has been a species of
<br />concern for many years because of its perceived low numbers and the vast
<br />transformation of its riverine habitat. Barren sandbars, the interior
<br />least tern's most common nesting habitat, were once a common feature of
<br />the Mississippi, Missouri, Arkansas, Ohio, Red, Rio Grande, Platte, and
<br />other river systems in the central United States. Sandbars are still
<br />common at normal river stages. on the Lower Mississippi River and on
<br />portions of other river systems. Sandbars generally are not stable
<br />features of the natural river landscape, but are formed or enlarged,
<br />disappear or migrate depending on the dynamic forces of the river.
<br />However, stabilization of major rivers to achieve objectives for
<br />navigation, hydropower, irrigation, and flood control has destroyed the
<br />dynamic nature of these processes (Smith and Stucky 1988). Many of the
<br />remaining sandbars are unsuitable for nesting because of vegetation
<br />encroachment or are too low and subject to frequent inundation. The
<br />number and distribution of interior least terns probably have declined
<br />accordingly.
<br />
<br />The interior least tern was listed as an endangered species on June 27,
<br />1985 (50 Federal Rel!ister 21,784-21,792) in' the following States:
<br />Arkansas, Colorado, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana
<br />(Mississippi River and it's tributaries north of Baton Rouge), Mississippi
<br />(Mississippi River), Missouri, Montana, Nebraska, New Mexico, North
<br />Dakota, Oklahoma, South Dakota, Tennessee, and Texas (except within 80 km
<br />of Gulf Coast). The States of Arkansas, Illinois, Indiana, Iowa,
<br />Missouri, Nebraska, Tennessee, Texas, Kansas, Kentucky, New Mexico,
<br />Oklahoma, and South Dakota list the interior least tern as endangered
<br />under State laws. Although not legislatively designated as endangered in
<br />North Dakota, the interior least tern is regarded as endangered by the
<br />North Dakota Game and Fish Department and conservation organizations
<br />within the State.
<br />
<br />Section 4 of the Endangered Species Act directs the Secretary of the
<br />Interior to develop and implement recovery plans for the conservation and
<br />survival of endangered and threatened species listed pursuant to Section
<br />4 .unless he finds that such a plan will not promote the conservation of
<br />the species. The Secretary, in developing and implementing recovery plans
<br />(1) shall, to the maximum extent practicable, give priority to those
<br />endangered species or threatened species most likely to benefit from such
<br />plans,' particularly those species that are, or may be, in conflict with
<br />construction or other developmental projects or other forms of economic
<br />activity. The interior least tern occurs along rivers which are heavily
<br />regulated by numerous dam and irrigation projects.
<br />
<br />The goal of this recovery plan is to describe actions for the
<br />conservation and survival of the interior least tern and to return the
<br />species to non-endangered status throughout its range. This plan
<br />summarizes available biological data, details various actions to s.tabilize
<br />and/or restore the interior least tern, and establishes criteria to remove
<br />it from the federal list of endangered species.
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