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1/21/22, 2:23 PM IPaC: Explore Location resources <br />https://ecos.fws.gov/ipac/location/HLNZHTJZZJEK7KYWMYZNAQDRRU/resources 6/11 <br />Probability of Presence Summary <br />The graphs below provide our best understanding of when birds of concern are most likely to be <br />present in your project area. This information can be used to tailor and schedule your project <br />activities to avoid or minimize impacts to birds. Please make sure you read and understand the FAQ <br />"Proper Interpretation and Use of Your Migratory Bird Report" before using or attempting to <br />interpret this report. <br />Probability of Presence () <br />Each green bar represents the bird's relative probability of presence in the 10km grid cell(s) your <br />project overlaps during a particular week of the year. (A year is represented as 12 4-week months.) <br />A taller bar indicates a higher probability of species presence. The survey eort (see below) can be <br />used to establish a level of condence in the presence score. One can have higher condence in the <br />presence score if the corresponding survey eort is also high. <br />How is the probability of presence score calculated? The calculation is done in three steps: <br />1. The probability of presence for each week is calculated as the number of survey events in the <br />week where the species was detected divided by the total number of survey events for that <br />week. For example, if in week 12 there were 20 survey events and the Spotted Towhee was <br />found in 5 of them, the probability of presence of the Spotted Towhee in week 12 is 0.25. <br />2. To properly present the pattern of presence across the year, the relative probability of presence <br />is calculated. This is the probability of presence divided by the maximum probability of presence <br />across all weeks. For example, imagine the probability of presence in week 20 for the Spotted <br />Towhee is 0.05, and that the probability of presence at week 12 (0.25) is the maximum of any <br />week of the year. The relative probability of presence on week 12 is 0.25/0.25 = 1; at week 20 it is <br />0.05/0.25 = 0.2. <br />3. The relative probability of presence calculated in the previous step undergoes a statistical <br />conversion so that all possible values fall between 0 and 10, inclusive. This is the probability of <br />presence score. <br />To see a bar's probability of presence score, simply hover your mouse cursor over the bar. <br />Breeding Season () <br />Yellow bars denote a very liberal estimate of the time-frame inside which the bird breeds across its <br />entire range. If there are no yellow bars shown for a bird, it does not breed in your project area. <br />Survey Eort () <br />Vertical black lines superimposed on probability of presence bars indicate the number of surveys <br />performed for that species in the 10km grid cell(s) your project area overlaps. The number of <br />surveys is expressed as a range, for example, 33 to 64 surveys. <br />To see a bar's survey eort range, simply hover your mouse cursor over the bar. <br />Lesser Yellowlegs Tringa avipes <br />This is a Bird of Conservation Concern (BCC) throughout its range in <br />the continental USA and Alaska. <br />https://ecos.fws.gov/ecp/species/9679 <br />Breeds elsewhere