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The recommended numbers objective for piping plovers on the central Platte <br />River is based on professional judgements in view of existing scientific data. <br />However, no analyses of population viability has been done for the central <br />Platte River. A more thorough analysis of such parameters such as habitat <br />quantity and quality, productivity, movements and survival may be needed in <br />order to better determine the minimum viable population needed and specific <br />population objectives. Therefore, based on current information, it is <br />reasonable to expect that 45 percent of 280 adult piping plovers (the Recovery <br />Plan goal for the Platte River), or 126 birds, should be attained on the central <br />Platte River as a 10 -year running average. <br />A.5.1.b. Distribution <br />The distribution objective for the central Platte River should be that no fewer <br />than 25 percent and no greater than 75 percent of the birds occur above <br />Kearney, Nebraska over a 10 year average. Nesting habitat can occur at both <br />sand pits and instream sites. <br />There are 17 bridge segments between Lexington and Columbus. Not all of <br />these bridge segments may be able to support nesting areas for plovers. In <br />addition, it may take many nesting sites to form a nesting area. According to <br />average nesting area sizes (2 plover pairs per nesting area )28, there would need <br />to be 32 plover nesting areas to meet the recommended objectives. Although it <br />is important to have a broad distribution of nesting birds, it would be difficult, <br />if not impossible, to attain an even distribution among bridge segments. <br />Therefore, a specific distribution objective by bridge segment is not being <br />recommended. However, to spread the birds out as much as possible, a <br />significant portion of nesting birds should occur both in the upstream and <br />downstream sections of the central Platte River. Kearney is chosen as the <br />splitting point to prevent too much of a skewed distribution. A greatly skewed <br />distribution (i.e., all birds nesting below, or above, Kearney) would not be <br />acceptable. Kearney is also about in the center of the current distribution of <br />piping plovers on the Platte River. <br />A.5.1.e. Fledge Rates <br />The fledge rate objective for the central Platte River should be 1.13 fledglings <br />per pair for a 3 -year running average for piping plovers. This recommendation <br />is based primarily on work done by Ryan et. al.,29 that described a fledge rate <br />for piping plovers as between 0.86 and 1.13 birds fledged per pair to maintain <br />population stability. In addition, the fledge rate recommended in the FWS <br />28 Nebraska Game & Parks Commission survey data. <br />29 Ryan, Mark K, Brian G. Root, and Paul M. Mayer. Status of Piping Plovers in the <br />Great Plains of North America: A demographic simulation model. Conservation Biology, <br />Volume 7, No. 3, September 1993. <br />11 <br />