Last week on April 6th we counted an estimated 228,600 +/- 18,200 Sandhill Cranes in the Central Platte River Valley. We experienced multiple warm days with high southerly winds which most of the cranes took advantage of to push forward on their migration north because on April 12th we only counted an estimated 3,500 Sandhill Cranes. We were not able to capture enough quality pictures during the flight on Wednesday to be able to calculate an error estimate. Because we counted less than 5,000 Sandhill Cranes, this week’s flight on Wednesday was our last flight for the season.
It is most likely that we did not capture peak abundance with our flights this year due to weather, variable crane behavior, and crew availability. Peak most likely occurred sometime between our week 6 and week 7 flights. Despite having a decrease from week 5 to week 6, we weren’t seeing notable decreases in the eastern portions of the river till after week 6 which is more typical after or right around when peak occurs.
This cranes season was definitely an interesting one. We started off with very comparable numbers of cranes to recent years but then as the river filled up we noticed strange deviations in the numbers from the norm. It does currently appear to be a result of a difference in crane roosting and foraging behavior and not changes in their population size but reasons for the change in behavior are still speculative. This illustrates why we do these flights and our other long-term monitoring year after year because without consistent and reliable data to look back on we could not effectively determine if and why short-term or long-term changes are happening within the Sandhill Crane population or their habitat. We are continuing to analyze our data to see if we can find more definitive answers for questions that came up this year.
Even though most of the Sandhill Cranes are gone, they leave a wake of green throughout the Central Platte River Valley as the prairies are returning to their spring colors!
Till the cranes return,