When you sit in a truck and watch birds through binoculars for months at a time, you start to speculate on what motivates them to migrate. There is evidence that it’s a hormone driven behavior but that just leads to the second question of what stimulates the hormone production.
The simple answer is temperature, a food shortage or the lack of open water in which to roost. But we know that birds will sometimes begin their migration well before those criteria are met.
This year we are not going to be adding much in the way of research data on that question. Our birds were spread out over three counties but late into the season, they were all still enjoying warm temperatures, ample food and plenty of marshy roosting sites — until Wednesday.
All of that changed drastically over the last few days when the snow hit, the temperatures plunged and the marsh froze solid. That left no doubt what made up their minds to leave this year.
All three teams have been driving the back roads and checking all the usual places but not a beep was heard. Wetlands that, a few days ago, were filled with Sandhills punctuated by a pair of white dots, are now silent, cold and lonely.
Braving strong winds directly out of the west, they took off and headed south. The skies were mostly overcast so they didn’t have thermals to carry them up. Rather than soaring at high levels and letting the winds carry them south, they had to flap their wings most of the way. Most of them made it past Chicago Wednesday so they aren’t out of the cold yet. Yesterday the winds in that area, up at a thousand feet were blowing from the west-northwest at 25 mph, so they’ll get a little push if they kept going.
In the interim, we wait anxiously for Heather to report on hits from their remote tracking devices. Numbers 29-16 & 39-16 that Colleen has been monitoring made it to Kendall County, IL late Wednesday….
It seems there is a like-minded person in Chicago who spent yesterday watching 30,000 Sandhills migrating over the city and heading south. During that vigil, his critical eye picked out white birds in their midst and he caught these pictures of what can only be number 30-16 and his adoptive parents 3-14 & 4-12. If you zoom in, you can see the lack of facial markings on the chick and tell that he is the one in the middle. Thanks to Samuel B. Burckhardt for sharing that information, otherwise I would still be search for beeps and waiting on a text from Heather.
The only chicks that remained yesterday were 31-16 & 38-16 that Heather and Jo have been monitoring. You likely noticed I used the past tense… They left yesterday!
We received a GSM email from 38-16’s tracking device, which placed him directly over Chicago at 1:50 pm yesterday.
So that leaves 70-16 in Portage Co., WI. He was released from ICF later than the others due to a wing injury. The two adults he was released with are already at their winter locations.
We are not sure what will happen next. Most, if not all, of the Sandhills are gone and there certainly aren’t any more Whooping cranes to show them the way. Capture, will be challenging. We will just have to see how it plays out.
Bev sent along this photo she took yesterday during an aerial survey. Can you find 70-16?
Bev says “a juvenile Whooping crane in snow covered corn stubble… how fun”! (click photo to enlarge)