WSP01978

• File Number: 8460.500
• Description: Platte River Recovery Plan
• Basin: South Platte
• Date: 9/1/1990
• Author: USFWS
• Title: Interior Population of the Least Tern - Recovery Plan
• Water Supply Pro - Doc Type: Publication

2. ,Determine current habitat reouirements and status.
Habitat alteration has been identified as one of the principal causes
of the current status of the interior least tern (U. S. Fish and
Wildlife Service 1985, Whitman 1988). Recovery of the species will be
affected substantially by the ability to identify and protect
essential breeding habitat and to intensively manage that habitat to
maximize productivity and survivaL Setting priorities for protection
of remaining sites and determining habitat management actions will
require detailed knowledge of interior least tern habitat requirements
and the availability and quality of existing sites.
21. Determine breedinE habitat reouirements and status.
Our knowledge of interior least tern breeding habitat
requirements has increased greatly during the past five years.
Data on seemingly adequate but unoccupied habitat is needed.
Comparison of habitat coniiitions among used sites along with data
on reproductive success will provide the information necessary to
set priorities for protection, and determine site-specific
management actions to enhance breeding habitat.
211. Assess the characteristics. includinE l"rey resources. of
breeding habitat.
The characteristics of breeding habitat must be investigated
across the entire range of the interior least tern. At
riverine sites, habitat variables to be measured should
include: nesting area and height above water level,
vegetative cover and'distribution, substrate type, and river
level fluctuations.' Other variables may be of particular
interest at local breeding areas. Measurements taken and
methods employed at various breeding sites should be
standardized to allow comparisons among areas. Few data are
available on food resources at interior least tern breeding
areas. Information on prey species occurrence and abundance
are needed, as are estimates of the likelihood of food being
a limiting habitat factor. The goals of these
investigations should be identification of the range of
habitat conditions tolerated by interior least terns,
determination of habitat factors that affect nest densities,
and elucidation of hiabitat conditions that may be related to
maximum reproductive success rates.
212. Quantify and evaluate available breedinE habitat.
As habitat assessment is undertaken, efforts to quantify
existing interior least tern habitat should be initiated.
The first task should be quantification of known and
potential breeding tiabitat. As habitat quality data become
available, existing sites should be evaluated with respect
to habitat, adequacy and deficiencies. Based on this
information, recomlnendations for site protection or
management actions should be given priorities. Remote
sensing techniques such as aerial videography (Sidle and
Ziewitz 1990) can be useful to quantify and, if possible,
rate interior least tern breeding habitat. Sandbars are
easily visible on satellite imagery of the Mississippi and
Missouri Rivers. A'catalog or compendium of interior least

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