We were treated to one of Nature's memorable spectacles yesterday soon after we returned home, about 4 PM. We noticed a few more birds than usual flying overhead and at first thought they were grey vultures, which are common here. Then we noticed a few more, and then a lot more were coming into to our little valley cul-de-sac. Within 15 minutes there were, by my estimate, a minimum of 500 to a 1000 birds in the air, maybe more.
I don't have a suitable wide-angle lens, so the birds you see in the photograph are just a fraction of the entire group. A few came close enough that I could see that they were definitely not vultures, but it took us a while to ID them, partly because it seems there is a lot of variation among individuals. I waited patiently with binoculars for individuals to sweep by, my Guide to the Birds of Costa Rica close by so I could compare to the plates. Clearly they were hawks, but which species?
At last my patience paid off. A lobe of the swirling, drifting mass of birds wandered over our house and I had a good look at them. Gavilán Pechinegro, aka Black-chested Hawk, aka Barred Hawk, aka Prince Hawk. These are not small birds. They measure 24 inches head to tail, and weigh about a kilo.
As twilight settled over our mountain I could see that the hawks were beginning to settle into the trees across the ravine. In another 10 minutes they were starting to settle in the trees in our upper forest. They were still about 200 meters away, however.
Tamara and I stealthily made our way up the back road to see if we could get a closer look. They were rather wary of us so the shots below were about the best I could do with the camera's optical zoom all the way to 12X. If we came closer they took off to join the larger group again.
Occasionally, one or a few would swoop very close over our heads from the trees above. I was amazed at the size of them. The Pechinegro is known for its large wingspan.
I can only wonder at the purpose of these kinds of mass migrations of birds that don't typically hang in flocks. My Guide doesn't mention this phenomenon (at least not near the species description).
Is it just that their timers all go off at the same time, or is there some reason why they need to stick close together as they make their expedition to their wet season hunting grounds?
I missed their morning departure by about 15 minutes because I slept in a bit today. Tamara said that before 6 they were already in a long, long serpentine line heading coast-ward. I thought I spotted a few stragglers, but they could have been the local vultures. Too far away to tell.
A treat indeed, even though it's a harbinger of the green season, which I don't really mind as long as it's not a deluge like last year!
One of the delights here in C.R. is the change of "seasons", which includes more than just a transition in the weather. Even within dry and wet seasons there are many subtler signs of change, new species of animals or insects coming and going, though not always in such spectacular fashion as these mass bird migrations.
Ciao cacao!
I don't have a suitable wide-angle lens, so the birds you see in the photograph are just a fraction of the entire group. A few came close enough that I could see that they were definitely not vultures, but it took us a while to ID them, partly because it seems there is a lot of variation among individuals. I waited patiently with binoculars for individuals to sweep by, my Guide to the Birds of Costa Rica close by so I could compare to the plates. Clearly they were hawks, but which species?
At last my patience paid off. A lobe of the swirling, drifting mass of birds wandered over our house and I had a good look at them. Gavilán Pechinegro, aka Black-chested Hawk, aka Barred Hawk, aka Prince Hawk. These are not small birds. They measure 24 inches head to tail, and weigh about a kilo.
As twilight settled over our mountain I could see that the hawks were beginning to settle into the trees across the ravine. In another 10 minutes they were starting to settle in the trees in our upper forest. They were still about 200 meters away, however.
Occasionally, one or a few would swoop very close over our heads from the trees above. I was amazed at the size of them. The Pechinegro is known for its large wingspan.
I can only wonder at the purpose of these kinds of mass migrations of birds that don't typically hang in flocks. My Guide doesn't mention this phenomenon (at least not near the species description).
Is it just that their timers all go off at the same time, or is there some reason why they need to stick close together as they make their expedition to their wet season hunting grounds?
I missed their morning departure by about 15 minutes because I slept in a bit today. Tamara said that before 6 they were already in a long, long serpentine line heading coast-ward. I thought I spotted a few stragglers, but they could have been the local vultures. Too far away to tell.
A treat indeed, even though it's a harbinger of the green season, which I don't really mind as long as it's not a deluge like last year!
One of the delights here in C.R. is the change of "seasons", which includes more than just a transition in the weather. Even within dry and wet seasons there are many subtler signs of change, new species of animals or insects coming and going, though not always in such spectacular fashion as these mass bird migrations.
Ciao cacao!
My husband and I enjoy spotting birds here in Puriscal as well. We really enjoyed your post about the Hawks.
ReplyDeleteThis is so cool!
ReplyDeleteThat was Amazing to get to see so many raptors.
ReplyDelete