The formidable talons of the larger falcons always impress me and this female Prairie Falcon gave me a good look at her scythe-like weapons. From the size of her hugely bulging crop it’s obvious that they serve her well.
These images are a little tight but I didn’t have any wiggle room – one is full frame and the other nearly so.
1/1600, f/9, ISO 500, Canon 7D, 500 f/4, not baited, set up or called in
I found this bird almost exactly a year ago along the causeway to Antelope Island where she typically hunted ducks. I don’t believe I’ve ever seen such a bulging crop on a bird of prey.
This image is a little different because the left foot is very prominent but is in silhouette which I thought made it appear even more ominous and threatening.
1/1600, f/9, ISO 500, Canon 7D, 500 f/4, not baited, set up or called in
This bird is inspecting and cleaning her feet after an obviously successful hunt and meal. My eye keeps coming back to those incredible talons.
I also notice the good look at the “cone” found inside the nostril of falcons. There’s a fascinating account of its function here if you’re interested.
Prairie Falcons often catch their prey with their feet but they can also strike their prey at high-speed with that formidable rear talon which typically delivers a mortal blow. I once watched (and photographed) that happen and I’ll never forget it. The falcon (it may have been this very bird) struck a Shoveler (duck) on the water in a surprise attack. Instantaneously there was blood spurting from the duck and it died within seconds. If you’ve never seen it before that attack can be seen here (you can see blood spurting from the duck just seconds after the attack in the first shot). My jaw literally dropped at what I observed.
I’m beginning to see a few Prairie Falcons on the island again but due to the drought the water has been so far from the causeway (along most of its length) that I doubt the falcons will spend much time hunting ducks there this winter.
Ron
Spectacular post! Photography, behavior, biology, art – it has it all!
I guess the closest thing we have to a Prairie Falcon is our migratory Peregrines. The large falcons are truly magnificent to watch.
I love the second image. Those talons work like hands. This is what I was saying the other day; birds developed wings as their upper extremity but use their talons like hands for grasping. Most bird’s talons are like hands. They have “opposable’ digits with the hallux acting as a thumb for ‘opposition’ (not always though). This made me read more, and I found two great articles which discuss this ‘thumb’ mystery within birds: http://news.discovery.com/animals/bird-thumb-finger-mystery-110904.htm and http://www.nature.com/nature/journal/v477/n7366/full/nature10391.html Great image and info, would love to see more of these series involving anatomical functions in raptors.
Maria: Just for clarity the Hallux doesn’t move on raptors. It is not opposible like our thumb. It is digit 4 that can move (in owls a Osprey) of raptors. They all can close, of course, but only digit 4 can move sideways to a backward position or remain forward like Digit 2 and 3. Digit 1 and Hallux are the same toe.
Bill
In birds with anisodactyl or heterodactyl feet, the hallux is opposed or directed backwards and allows for grasping and perching. It doesn’t have to move, but the fact that it’s placed backwards MAKES IT opposable.
OK. You are correct. I thought a toes ability to face forward or backward was the definition of opposable but it is the ability to be placed in resistance. So one could say the Osprey and owls (as well as some woodpeckers) can create the situation of two opposable digits.
Sorry for the confusion.
Bill
The confusion stems form the term “opposition” which applies to humans and some apes; humans having true ‘opposition’ (precision grip) with the thumb that sets them apart from all species. The term ‘opposable digits’ came into use so as to not confuse prehensile grasps with having to have the #1 digit (thumb or hallux), and many species that have prehensile grasps that do not involve digit #1.
Prairie Falcons present an odd contrast for me. The only time I have heard the whooosh of wings in the field was with prairie falcons… twice. It is a sound never to forget, pure lightning hunting speed. (I have also heard it while banding, but it does not present the same unexpected thrill.) They are also one of only two birds I’ve ever seen with crops so full that they almost couldn’t fly. (The other was a golden eagle on a roadkill wild pig.) But images, as different as they are, are the sign of a magnificent and amazing hunter.
Love me some prairie falcons.
Terrific images, Ron. You keep surpassing yourself (and spoiling us). At this season I often send calendars to friends featuring photos of owls or other raptors. I’m afraid those images are looking pretty uninspired at this point! Perhaps you might consider doing a bird of prey calendar sometime, possibly sharing the proceeds with a worthy raptor-related charity? Or have you already turned your hand and lens to that? Not that you need more projects! If you ever do a calendar, I’m an eager customer.
Very interested in your observations about (diurnal) raptors removing and discarding intestines from prey. I looked at the various images that you linked. Frankly, I’m surprised that your observations have so uniformly showed discard. Because intestines spoil fastest, many folks who keep captive raptors remove the guts of prey animals before feeding. Others of us feed with guts intact, then leave it to the discretion of the bird to eat or to discard. The reason I do this (speaking for myself) is because I believe that predators (even obligate carnivores) may benefit from small amounts of unusual nutrients found in the stomach and small intestine even of herbivorous prey.
As for the large intestine (colon), we keep learning more about the importance of very diverse bacterial colonies in a healthy colon, and ingesting many of these once-scorned bacteria is now looking essential. (A new treatment for intractable human cases of irritable bowel syndrome is not a drug, but a “fecal transplant”… which is just what it sounds like.) So again, I leave the choice of eating colon-cum-feces to the bird.
My captive raptors tend to eat or discard the intestines based on relative appetite. None of my birds is thin! But when really full from a meal, the intestines may get flung aside, typically onto me if I’m feeding the bird on the glove. It helps me remember not to wear good clothes into a mew! The colon, with its load of feces, is most likely to go. But I have to say that it’s quite rare for the small intestine to be discarded, and then only if the bird is especially full and fat. There sure aren’t many fat wild raptors, so why are they discarding even small intestine which isn’t, by my current degraded standards, especially yucky? And in cold weather when food is scarce??
One small thought is that wild raptors are naturally eating fresh prey all the time. My captive birds eat prey that has been frozen. So maybe it’s easier for wild birds to get their quota of essential bacteria without consuming the gut very often? And perhaps at some point ingesting more bacteria, protozoa, fungi may not be better? But why they’re discarding small intestine — that in your images doesn’t even necessarily contain “sausages” of proto-feces — does surprise me. When the prey is fresh-killed, not cached, it presumably wouldn’t be because the innards spoil first. It is interesting that you apparently aren’t seeing birds discard the stomachs of prey (are you?), so the nutritional need for stomach contents of prey may be real.
Considering owls doesn’t seem to help, at least superficially. The stomach acid of diurnals is far stronger than that of owls (for instance, owls don’t digest bone) so it would seem that if there are dangerous pathogens in the guts, diurnal raptors could be better equipped to combat them.
Clearly I haven’t advanced the ball on this question. If anything, perhaps I’ve suggested why some (captive) raptors DO eat intestinal material. That makes understanding why wild birds routinely ~don’t~ seems even stranger to me. Thanks for a stimulating observation. I’ll chew on it.
Maya, Your last sentence made me laugh.
I don’t think I’ll be doing a calendar anytime soon – too much work and I can just barely keep up with my blog (in fact I may soon have to post less often than daily for reasons of time). However, I have recently donated two images to the 2014 Hawkwatch International calendar, a fundraiser for a great cause.
http://hawkwatch.org/components/com_virtuemart/shop_image/product/2014_HWI_Calenda_5241d125d4005.jpg
You provide fascinating information and questions that I’m very curious about, as you apparently know from reading some of my previous posts on the subject.
I see intestinal discard constantly from raptors who don’t normally swallow prey whole. I’ve never noticed them specifically rejecting the stomach but often times it would still be attached to the small intestine and when relatively empty would be difficult for me to discern from the intestine through my lens.
I strongly agree with you about the possibility that they (species who tend to swallow prey whole) may get trace nutrients by eating stomach and intestinal contents of their prey (but wouldn’t All raptor species?). That especially makes sense for obligate carnivores (I’ve done some internet research on that in the past and it fits with my training as a biologist). And anyone who has taken too many antibiotics of certain types certainly knows the price to be paid for killing natural intestinal flora. “Fecal transplant” indeed!
I see raptors rejecting both large and small intestines in times of plenty and times of nutritional stress. In fact, I can’t remember seeing (or photographing) one eating them specifically rather than incidentally. Just my observation, nothing conclusive of course…
In the end I don’t know why so many raptors reject them. I’ve often wondered if it’s simply because they don’t taste good (obviously, species who swallow prey whole don’t have to concern themselves with that). I’ve actually seen behaviors that insinuate to me that they’re strongly repelled by the “thought” of eating them. Perhaps it’s the smell???
I know that I don’t eat things that are good for me that I don’t like the taste of…
Great comment, Maya!
“There sure aren’t many fat wild raptors, so why are they discarding even small intestine which isn’t, by my current degraded standards, especially yucky? And in cold weather when food is scarce??”
Maya: The intestines may offer nutritive value in the form of vitamins, etc but not the needed calories. Also many raptors (especially falcons) don’t find them palatable (by their tongue) so they flick them away.
Bill
Intersting comment…as usual. Happy holidays!, Bill.
Are yoU having an unusually early, hard winter? Account of shivering Barn Owl attempting to hunt breaks my heart!!!
Fantastic photos! I have to admit that I’m in agreement with EC there – a great way to differentiate naughty from nice!!
If you had taken this photo recently I would assume that the crop was full of a slow-moving elf. Santa could make good use of those weapons in weeding out the naughty from the nice.
Frivolity aside, these are glorious images. Beauty and function.
“If you had taken this photo recently I would assume that the crop was full of a slow-moving elf.”
Loved that, Elephant’s Child!
I love how large a falcons foot is, compared to its body. It is apparent in your images. And the bulging crop. Wow. Very neat photos Ron, thanks for sharing.
That full crop, reminds me of a juvenile sharp shrink I did a watercolor of. He was all puffed up because of the cold and snow, you could see a bit of red on his talons and he looked very satisfied…one claw up. I called it, “happiness is a Full Tank”.
Grandma, what sharp fingernails you have!!!!
Amazing shots and fascinating material. Thanks for sharing Ron!
Ron: I have taken the following comments from your linked text on the earlier Prairie photos:
“Mark Runnels
November 11, 2012 at 8:18 pm • Reply
Hi Ron,
I have never seen a falcon hit a duck in the water that came out on top. I have had several very young birds try to take a duck off the water, but they always wound up getting wet (me too most of the time) and learned to wait for the ducks to leave the water. I am not sure that they could lift the duck free of the surface tension of the water. Very creative of this bird to wait for it to wash ashore.
It is interesting that this is a Prairie, I don’t think a Peregrine would risk the same attack. the generally wont fight with prey on the ground, let alone in the water. The fact that this is a 2-3 year old bird says that she has probably done this before. I wonder how common this behavior is among Prairies?
You are probably correct that the falcon is conscientious of the direction of attack and is trying to stay out of sight as long as possible. I have watched Cooper’s hawks fly low and keep a bush between themselves and the prey bird until the last possible moment. I have also seen Ferruginous hawks work as a pair. One will fly openly beyond the danger range and all of the prairie dogs will watch it while another hawk attacks from behind. Kinda the same idea. One hawk is distracting the prey so that the other can approach without being seen.
Beautiful pictures. I love contrasting the wild behavior with that of our trained birds.
Thanks Ron.
Mark”
You had asked if it was common for falcons to attack from behind. There are several advantages for the raptor to attack from behind rather than head on or from the side.
The more vulnerable prey areas for a quick kill are within the path of the falcon and for a longer period of time. The body and back of the head are the areas the falcon would prefer to strike. Coming head on offers a greater chance for the duck/prey to dodge the blow or for the falcon to be hit itself by a sudden change of direction by the duck.
“It is interesting that this is a Prairie, I don’t think a Peregrine would risk the same attack.”
I agree with this. Prairies often are taking ground prey while Peregrines rarely do. They are usually pursuing birds. Gyrfalcons, like the Prairies do both. So the Prairie is more comfortable with a duck “on the water”. Taking a duck (especially one this size) while in the air offers a falcon the opportunity to glide the prey to shore. Each of the large falcons have different wing loading (this also enters into the picture for the Peregrine’s vs Prairie’s likelihood of attempting such an attack).
You also mentioned in your comments about team hunting. Harris Hawks often hunt in packs while numerous other raptors will hunt in pairs. Balds (one example) are often seen using team work (especially on waterfowl). The first Bald attacks the duck on the water. The ducks response is to dive. Upon surfacing it is grabbed by the second Bald.
Bill
Great information to fill out this post, Bill – both from you and from Mark. Thank you.
I tried to research one thing and mostly struck out – maybe you or someone else can help. How often do Prairie Falcons rake their prey with their rear toe during the attack and then come back to the victim? I get the impression that they usually simply grab the prey with their feet, either in flight or on the ground. Correct, or not?
I will attempt to get some numbers for you Ron but its difficult to answer that as you might imagine because of the numerous situations that can arise. First off any ground quarry is going to be grabbed rather than raked. So depending on the specific Prairie’s main prey (often regional) so might that bird’s ration be or even that regions Prairie’s ration be.
Generally speaking if the prey is avian two results can happen. The Prairie will stoop (strong, fast dive from height) and the speed is the factor mostly determining if the falcon will bind or strike. If the falcon should miss on the stoop the falcon will normally change direction (so as to rise up above the potential prey again. The result of mostly momentum. Then will dive again but now from a much lower height and therefore slower speed. Now the falcon is more likely to bind because a lethal blow is less possible.
If the “angle of attack” is very low (we refer to these as a tail chase) again speed will be low so a bind will normally result. One must consider the species, fitness and experience (also hunger motivation) as to which species use which strategy at which time.
Sorry I can’t give a definitive answer but like many topics we discuss here much of the discussion simply touches on the periphery of the many details which enter into the topic and complete answers.
Bill
Thanks, Bill.
I should have asked “how common” is it rather than “how often”. Once again you’ve provided useful and interesting information.
Love your answers Bill…always so detailed! I thought I might mention too that depending on the prey and what area they live influence the way a hawk or falcon hunts. If it works, they will do it again. Sakura caught a black bird, in what I call frustration. She was in pursuit of a cotton tail and was hit by a stiff gust of wind. She was “thrown” upward to the top of the arbour in front of my house. She was immediately harassed by a black bird. She grabbed it, and ate it. Its a habit that I haven’t been able to stop. In the area where I live, Red Tailed Hawks dont bother with them and re often are seen being chased by black birds.
Tim
Tim: Thanks. Yes, success will result in future attempts. A big part of the bird’s learning. Especially our falconry birds which learn much by what we set up for them rather than by example which the wild birds are taught by their adults. (I’m talking much about captive bred or imprints here although many passage birds learn additional techniques and prey via this method.) “Accidental” or “designed” success via entering can change the whole primary prey for some of our birds. Some of it is of course very intentional on the falconer’s part because that is the most common prey available in their vicinity. This also occurs often when a specific species is utilized in a region where they naturally don’t exist.
As Mark mentioned we often see our young birds especially attack something an older bird wouldn’t attempt. Mostly because they don’t know better. We then see an expansion in prey or technique. All brought about because of not knowing better. (Reminds me of teenagers that develop new skills or sports because no one told them it couldn’t be done. One form of creativity). Perhaps this is evolution or adaptation. Success to the bird’s way of thinking is difficult to then stop if it happens to be a behaviour we would prefer they didn’t display. But conversely it’s something we love if its a behaviour we want.
Bill
Bill
Wow! Great shot of her inspecting herself. The shot of her on the other page, wings spread, dragging the duck and looking directly at you, is an awesome shot! And again, love the story behind the pics. So interesting!
The image you describe is one of my favorites too, Patricia. Thank you.
Fantastic shots Ron!!
But, where is the prey he demolished??
Dick, I never did see the prey in this case. She was on this rock, preening after her meal, when I approached her.
Ron, she needs those talons to get enough prey to yield such a big crop.
Great detail of a good meal.
Thanks for reshowing the take down of the duck you posted before.
Thanks, Diana.