While we were unable to sneak in a week 7 survey, we completed an early week 8 count on the 3 rd of April. Between Overton and Chapman we estimate 391,000 +/- 190,000 Sandhill Cranes around the Platte River. There were favorable migration days this past week so many cranes left, especially in the east. The majority of cranes (~75%) are now found west of Shelton. The next few days have winds forecasted from the north so these birds are likely to stick around over the weekend into next week. While overall numbers are on the decline, there are still huge flocks of cranes in the 80 miles we survey. Many of these cranes, especially around Kearney, were in groups of 10,000 seen both in the river and in the fields early in the morning! This is typical of cranes within the Central Platte throughout migration but I thought it worth reminding that just because “peak” is over doesn’t mean that there are no more cranes to see. However, we usually see large drops in numbers between week 8 and 9. Some might be questioning the larger error (+/-) we reported this week or even questioning what the error means at all. The number we include after the +/- allows for us to communicate confidently the numbers we report. During our surveys we estimate groups of thousands of cranes within seconds. While we practice to be as accurate with these estimates as possible there is no way for us to be exact in the moment when tens of thousands of cranes are passing under the plane at any given moment. We alleviate this issue by capturing pictures of roosts when we can and comparing the estimated number of cranes to the actual number of cranes (yes that does mean we go through and count each crane in multiple pictures each week). The difference between the actual count and the estimated count provides us with the ability to calculate the error for the survey. Some weeks we are more accurate on our estimates and other weeks we might be off. Regardless, this statistical approach allows us to report numbers we are confident in and are able to tell the story of the migration. This week our error (+/-) remains higher as the new crew continues to learn and refine their skills with the protocol we've had in place for 10 years now. While I have not been able to be the crane counter this season, I am so grateful for our team being able to adapt and take on challenges to be able to still collect data and share numbers with the community.
Till next time,
Bethany
