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09/25/2018 Event Code: 06E24000-2018-E-04333 2 <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 <br /> FAQ "Proper Interpretation and Use of Your Migratory Bird Report" before using or attempting <br /> to interpret this report. <br /> Probability of Presence ( ) <br /> Each green bar represents the bird's relative probability of presence in the 1 Okm grid cell(s) your <br /> project overlaps during a particular week of the year. (A year is represented as 12 4-week <br /> months.)A taller bar indicates a higher probability of species presence. The survey effort(see <br /> below) can be used to establish a level of confidence in the presence score. One can have higher <br /> confidence in the presence score if the corresponding survey effort 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 <br /> the week where the species was detected divided by the total number of survey events for <br /> that week. For example, if in week 12 there were 20 survey events and the Spotted Towhee <br /> was found in 5 of them, the probability of presence of the Spotted Towhee in week 12 is <br /> 0.25. <br /> 2. To properly present the pattern of presence across the year, the relative probability of <br /> presence is calculated. This is the probability of presence divided by the maximum <br /> probability of presence across all weeks. For example, imagine the probability of presence <br /> in week 20 for the Spotted Towhee is 0.05, and that the probability of presence at week 12 <br /> (0.25) is the maximum of any week of the year. The relative probability of presence on <br /> week 12 is 0.25/0.25 = 1; at week 20 it is 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 <br /> probability of presence score. <br /> Breeding Season ( ) <br /> Yellow bars denote a very liberal estimate of the time-frame inside which the bird breeds across <br /> its entire range. If there are no yellow bars shown for a bird, it does not breed in your project <br /> area. <br /> Survey Effort (1) <br /> Vertical black lines superimposed on probability of presence bars indicate the number of surveys <br /> performed for that species in the 1 Okm grid cell(s) your project area overlaps. The number of <br /> surveys is expressed as a range, for example, 33 to 64 surveys. <br /> No Data (—) <br /> A week is marked as having no data if there were no survey events for that week. <br /> Survey Timeframe <br />