It looks as if the pair of American kestrels (Falco sparverius) on Stephen Barnard’s Idaho property (he built them a Kestrel Condo on the side of his garage) may soon be laying eggs. Here is a video of the female, Natasha (the male is Boris), as well as some photos.
The first video, says Stephen, “might be another mating interlude. It doesn’t take them long.” He adds, “By the way, I set the camera up on a tripod, start it recording, and leave it.”
Stephen’s notes and descriptions are indented:
Here’s a photo of the radiant and fertile Natasha:
“The happy couple”
Boris.
Note the moderate sexual dimorphism in the photos. Males are rusty above and have slate-blue wings. Females are rusty all over with black bars on the wings and back, and are slightly larger.
Natasha:
Boris and Natasha:
Boris:
Natasha in diffuse light, which I think brings out the detail nicely:
Natasha with a vole for breakfast.
Stephen also posed a question about the sexual dimorphism (rare for raptors, but not that pronounced compared to, say, birds of paradise):
What I find remarkable about them is sexual dimorphism of an unusual kind. I’m no bird expert, but in my experience different bird sexes tend to be either very similar (like bald eagles) or very different, with the females considerably drabber in the latter case. The kestrels don’t follow that pattern. Both Boris and Natasha have striking markings, in some ways similar (the head) and in some ways different (the breast). Boris has bolder markings, but Natasha can by no means be called drab.
I can make up stories about this (which of course is all we have), but I leave it to readers to suggest possible answers.
And two more that arrived yesterday evening (I can never see enough kestrel photos).
Boris:
Natasha:
Is Boris missing a leg in the last photo?
It’s common for birds to rest on one leg.
Excellent pictures! Agreed we need more kestrals ’round here.
I’m not so sure we are having too many. The rabbits around here are in short supply and the ducks have babies now.
Kestrels are really small — about the size of a blue jay. A rabbit would be much too big for one, and a kestrel taking a duckling is extremely unlikely.
I was meaning pictures, of course.
+1. Gorgeous birds, and great pics of them.
Gorgeous! And luck you Stephen. I have tried to get kestrels to nest near my house so I can watch them daily but so far, no takers!
Lucky, not luck.
About the slight dimorphism. I’m guessing it means Natasha is kind of choosy, but not all that choosy. And Boris is kind of faithful, but not all that faithful. Doesn’t answer your question of course.
Great photographs, BTW.
Boris with his spotted chest is a right dandy. Great pics Stephen!
Re dimorphism
From the link:
Being so small, these kestrels are preyed on by a number of different larger raptor species & also by snakes – perhaps the habitat difference, outside of their debutant season, accounts for the plumage difference. Also the chicks are sexually dimorphic before they fledge! This [I’m guessing, not being a birdologist] supports my habitat theory
Unrelated:
I suppose therefore the dimorphism may be even greater than is apparent to us – we don’t tend to observe creatures at the light spectrums of their peers, their prey & their predators. Would like to see more photos that accommodate UV etc
I was thinking of a more general story, which is that in species which share the cost of rearing the kiddos there are fewer differences in their sexual selection. In a more stereotypical situation, males do not share the task of rearing young and so females choose males based on a display of the quality of their genes, or based on the value of a territory that a male defends. Females are choosy and males compete to be chosen in those situations. Then, males tend to be boldly colorful or big and belligerant, to mention extreme outcomes of those situations.
But in species like bald eagles (and I expect kestrels), both sexes rear the young cooperatively, so their criteria for selecting a mate is more similar and as a result are more similar in appearance.
But I like your angle too – that kestrels each experience different selection factors at other times in a season, and we should weigh that as a factor for why they are somewhat different. Also what they see may be different from what we see.
I think Natasha would blend in with a nest composed of twigs and hay better than Boris would.
But both male & female do nest duties
Wonderful photos. I never get to see kestrels up close, usually spotting them from the car sitting on a wire or fence, or during their fluttering hovering hunts, so I’d never noticed the dimorphism. How cool! Now if only I could attract a pair to my acres, I’ve an abundance of meadow voles.
Take out an ad [in kestrel language that would be a correctly sized & positioned bird box]. I don’t know about American kestrels, but my British garden birds are fussy – there’s one box of three that’s never used & I’ve no idea what the problem is. The birdies inspect it regularly in season & then go elsewhere.
That’s exactly why I asked for a photo of the he nest box from the last kestrel post. However, I do have two couple of red-shouldered hawks that frequent my land, so maybe they are a deterrent to kestrel visits. I don’t know how much inter-species competition there might be.
The kestrel can sometimes best the larger hawk. As per HERE [Photos]
Oh, excellent! Makes sense, I guess. They’re smaller and more maneuverable. But, I do love my red shouldered hawks, they are quite strikingly colored. I’m just happy I finally have my own place and my “own” wildlife, including two resident ornate box turtles, so I’m ok with the hawks instead of kestrels for the time being.
The Belted Kingfisher also has an unusual sexual dimorphism. In this case, it is a female that is slightly more colorful. Both sexes are blue and white, but the female has a rust colored band across her belly that the male does not.
I think the male and female turkey vultures look the same. These birds and pictures are so cool and beautiful.
Given the distribution of bird species in the sexual dimorphism spectrum, it seems likely that a few species will be intermediate between the large groups at the ends (no dimorphism and great dimorphism).
Isn’t sexual dimorphism for body size somewhat common in genus Falco? That’s what I’ve heard/read anyway, with the female being larger.
And: great photos Stephen, thanks!
Beautiful pair, and photographed well!
Wonderful pictures; many thanks. You have a real gift for this art.
On a closely related subject, may I draw people’s attention to a great programme on BBC2 yesterday (Thursday): Super Fast Falcon, all about peregrines. It switched between an English guy who trains them (from the egg!), and a family with two chicks growing up in Chicago. Stunning photography, including high-speed stoops. It is on the iPlayer for the next month. Well worth looking out for.
Reference to the male hawk or falcon as a “tercel” is from falconry. The male is a quarter or third smaller then the female.
And now, oh my brothers (and sisters) as Alex would say in “A Clockwork Orange,” comes the weepy part of the story. These little guys are really vicious. I used to live in Idaho, too, and a kestrel stationed itself atop the tallest tree in my yard. They’re very fond of little songbirds. Occasionally I would find patches of blood and feathers when I came home from work. One time a plumber came to install a dishwasher. As he was leaving, he looked out my back window, and saw the kestrel chasing its prey. They are amazingly agile. A little bird, a goldfinch, I believe, was maneuvering wildly in the air, but the kestrel, although much bigger, was matching every twist and turn. The only chance little birds have to escape is to dive into thick brush where their shorter wings are an advantage. In a few seconds, the kestrel seized its prey and tore it apart and devoured it in front of the plumber (kestrels are not dainty eaters). All he could say was, “Oh, my God!” I don’t see any videos on YouTube that show kestrels demonstrating their incredible flying skill in this way. Maybe its better left to the imagination.
They’re so cute!
These photos are excellent, Stephen. Thanks!
Terrific photos of a stunning pair. Can’t wait to see their brood.