Saturday, June 26, 2010
Learning Crane Language
UNISON CALL OF A PAIR OF SANHILL CRANES, 1999
Laure Ferlita’s nice comment to my last blog post make me realize I didn’t elaborate on how I can tell a female from a male crane, only that I can easily tell these cranes apart because the female has a broken toe, permanently frozen at an odd angle. But first I had to figure out which sex had the broken toe. It’s not easy. The male is usually larger, but not always. Their plumage looks the same. So how do you tell?
I once thought how much red how on their forehead was the giveaway. The red can be quite small, or stretch back to a spot behind their eyes. Many years ago we were watching a sandhill crane nest. It was a blustery, snow-spitting day. I succeeded in setting my scope up inside our van so Dale could photograph from the front seat window and I could peer out of the same window to draw.
We had been parked and watching for over an hour. Dale dozed off, still holding ‘Big Bertha’ (our 500mm lens) in his lap. I was enjoying the chance to draw.
The cranes had exchanged places. The newcomer had a lot of red it its forehead. I was working on these sketches. My notes say it all too well – I did have the question marks in my original notes:
2:05 pm She (?) stands and bugles several times. The mate has arrived. Both bugle. This small valley resonates with their calls. The newcomer reaches down with its long bill and gently rolls the pale, lightly mottled egg. One egg.
After a brief interlude of nest building, one walks off and out of sight. The newcomer rolls the egg again and starts to settle down onto it. Ouch! That position isn’t quite right. He (?) stands again and attempts to turn. The crane is standing on its own foot! First it must untangle its toes, then settles down again. With its back to us, the crane tries again, but that position isn’t right either. He(?) stands and pivots to the right and settles for a third time. Better.
2:20 PM: He preens on the nest. Still one dab of snow on the nest. More is falling, but it isn’t sticking.
2:25 PM: Stands, then eases down and sits on his (?) elbows and looks around. I think he is trying to find a solution to this lumpy problem (the egg).
2:30 PM: Still sitting on his elbows. He (?) is pumping sort of – deep breathing?
2:32 PM: SHE just laid an egg! Damn. I missed the actual egg laying by a hair. I was busy drawing her head .. and looked back to the crane and saw she was standing over two eggs. Damn! Damn! Damn! I should of, could of, seen that egg pop out.
I really was that clueless as to what was going on! I obviously needed to learn more about cranes. Over the years I have, both through reading and watching. One spring we tallied over 130 hours watching at Floating Island Lake. Of course we weren’t always watching the cranes, but we learned a lot.
Sandhill cranes have a specific neck-stretched-out posture when about to fly.
A bird on the nest lays its long neck flat out when a wolf, coyote or dog is too close; and they have a wonderful quiet ‘churring’ sound we only hear between pairs during special moments in their life; how much red they show on their forehead is a reflection of excitement, the more red the more excited the bird is.
But how to tell a male from a female? We pondered on the issue with George Bumann, a wonderful naturalist / sculpturer who lives just outside the park. The next day is came up to us with a treasure, George Archibald’s description of the ‘unison call.’ George is one of the founders of the International Crane Foundation.
When paired sandhill cranes bugle in unison, the male’s bill shakes more slowly and tends to point straight up; the female bugles a little faster and her bill does not reach straight up. Once we realized one had a broken toe, it was only a matter of time before we knew the sex of that crane. Looking in my 1999 journal I realized I had painted a unison call without knowing the significance of the stance.