One pair of caracaras almost drove me nuts trying to find their 2010 nest. Their 2009 nest was a single palm in open pasture away from a marsh. The tree having no lianas and only a few inflorescences to anchor it, winter winds had shredded the nest and the birds did not repair it. I don’t blame them for moving, but wonder why they chose that particular tree in the first place? Maybe they are a relatively young pair and it was their first nest, or maybe I just don’t know enough about caracaras.
The 2009 nest wasn’t very close to a favored perch – a half-dead pine – but the pine was adjacent to a small marsh and was probably a good perch to hunt from in 2009 because then it was wetter and produced more prey. The marsh is dry this year; in fact, all the marshes anywhere close to their 2009 nest are dry so far this year. Nonetheless, this pine is still used occasionally by the pair and is where I first saw them, and thus subconsciously I concluded that it was a good place from which to follow them. Wrong! They all but stopped perching there after I started looking for their nest.
On Day Two, they began flying from somewhere in the east, passing over the pine perch and landing in a pine snag to the west. I walked over there and spied a disheveled stick nest in the snag, definitely not a caracara’s, but it didn’t look active. Possibly the caracaras had a nest in one of the nearby palms? But the caracaras didn’t spend much time there. They just went over briefly and then went to some place in the east, again and again. It turned out that a pair of ospreys were actively building that nest and the caracaras didn’t like it one bit. But one osprey can run off a pair of caracaras, so perhaps the osprey were one of the reasons the caracaras moved their nest?
I walked over to the east side of the territory where I thought they were coming from and found what seemed to be a fine spot for a nest. It had several snags offering commanding views, a larger (albeit dry) marsh and a palm with the right amount of lianas and inflorescences (a liana is a woody vine). But there was no nest there. At this point, I had also sat hidden and quiet for several hours in each of several places watching for caracaras to see where they came and went, hoping that they would reveal the location of their core territory. A core area is where the nest, one or more high perches and a nearby dependable source of food are co-located and competitor core areas are distant. Once you find the core area, you hang out and you will inevitably find the nest. I walked all over their territory over a second half-day looking for activity that would lead me to their core area, all to no avail.
Near the end of that day, when the caracaras were gone I snuck over to a palm hammock that gave a view of the old nest, a potential nest tree and a flyway they had used repeatedly to launch harassment attacks on the ospreys. I waited and waited but saw nothing, so decided to move. At about official sundown, I snuck carefully and quietly around the edge of the hammock to a second observation post, spadefooted my way backwards into a dense clump of tall grass where I believed I was well-hidden, and looked up into the bemused eyes of the male caracara sitting on a fencepost about 100 ft in front of me, and got that old flush-cheeked feeling again. You know how it is when you’re busted but you bravely bluff your way through just in case your opponent doesn’t care? Well, that’s what I did. “Ok, you spotted me,” I thought, “so what are you going to do about it? You still have to go to bed tonight, and I’m not leaving until after your bedtime.” He answered by leaping off the fencepost flying straight toward me, and then banked to his left and rocketed away along the tree line. Care to guess whether he lost me?
The next day, I noticed them headed a little south of “the” east that I had investigated earlier. Following up, they proved to be using power poles and an oak for core area perches a lot closer than the east area. “Ahah,” I thought, “all I have to do now is look at all the cabbage palms in there and I’ll for sure locate the nest.” But all the cabbages in their core area are tall (at least for South Florida), easily 70 – 80 ft, which makes it very hard to discern nests in trees containing arboreal thickets. I looked and looked, yet could not find the nest. I sat down in the shade of a bush and waited for them to show it to me even though they knew I was watching. That evening they pulled the standard tricks of male-decoying-me-so-female-can-sneak-into-nest (which worked) and right-at-dark-male-zips-into-nest-from-fifth-dimension (which also worked).
The next day I waited until both birds left the core area. I was just about to run over to a pre-selected, hidden observation post, but just then, the female came back. Fortunately, she immediately dropped down out of sight right over there, so I thought that if I ran as fast as I could that perhaps I could get under cover behind the barn before she flew up to where she could see me. I did and she didn’t – good so far. She had landed on a utility pole behind the landowner’s house, and from there she flew over to the nest tree. I didn’t know it was the nest tree at the time because I had already looked for a nest in that tree without finding one, plus she was sitting way out on an inflorescence outside of the crown’s foliage instead of hiding inside the crown. She sat there for awhile, flew down to the ground where I couldn’t see her, flew up into a second palm and sat on one of its inflorescences, and then a few minutes later flew off to the east. I knew either of those two palms might well be the tree.
This was good and this was bad. It was good because the area was open and everything was easy to see, plus there were good hiding places from which to observe the birds. It was bad because I would have to lurk around the edge of the pasture immediately adjacent to the landowner’s back yard and hide in clumps of vegetation. If their kid happened by and spotted me, it would probably would have been ok because kids are cool, but if poppa was an angry man and happened by…? Oh, the horror… Because I had been trying to not bother them and had not even met them, I really didn’t want to greet them accidentally at that hour, but I had been working on this nest too long, I was in the right place at the right time and no one seemed interested in visiting the pasture, so I blessed my camo and proceeded. Call me a wild man.
I knew the female caracara would go to the nest well before official sundown, perhaps by an hour or more. I had maybe 1.5 hrs before sunset, so I ran over to the hammock that was close to the two potential nest trees that she had shown me. I found a hiding spot at the edge of the body of the hammock and waited. I didn’t like that spot so moved to another that was on the tip of a point of the hammock, more exposed to humans but still well hidden from caracaras. The two birds returned to core perches before long and gave no indication that they were aware of my presence. The pair left again and I used that opportunity to move quickly to yet another post, closer to the perches and the presumed nest trees, but even more exposed to wandering landowners. When the birds returned I discovered that a critical part of my view was blocked by vegetation, so when they left again I moved to yet a fourth, even more exposed yet still well-hidden spot. I felt like an accomplished sniper when they returned unsuspecting. About 10 minutes before official sundown the male flew off and when I looked back the female had vanished. I did not see her again that day. Old trick.
Shortly, the male flew back to the utility pole and at 19 minutes after official sundown, he flew to the nest tree. To confirm that it was the nest tree I walked over and used my presence to cause him to fly away from the tree, because if he returned I could be almost certain that it was indeed the nest tree. The poor fellow couldn’t see me until I was almost directly underneath him due to the darkness, and when he realized I was there the expression on his face was absolutely priceless. He was open-mouthed and his demeanor fairly shouted, “Where in Hades did YOU come from!” When I left the tree, he was so anxious to return to it that almost as soon as I turned my back he flew in. This time it was he who was busted, I gleefully note.
There is so much at stake that we have to be extra careful that we finger the correct tree, so I returned the following morning to visually confirm that there was indeed a nest in the tree and that they weren’t just spending the night in a plain old palm. The nest was so new and threadbare that I could see her plainly through the bottom of it, not at all like my earlier post on the usual thickness and opaqueness of their nests.
Finding this nest was a lengthy challenge – it’s a good thing that I wasn’t being paid on a lump sum basis!
Dicromantispa interrupta
Mantisfly
Showing posts with label caracara nest. Show all posts
Showing posts with label caracara nest. Show all posts
Tuesday, February 9, 2010
Saturday, February 6, 2010
Caracara Nest and Nest Tree
When I first learned last year that I was going to be looking for nests of the crested caracara in South Florida, I reviewed information available on the internet about their nests and nest trees. I wanted to know what I was supposed to be looking for in terms of what species of trees, how high off the ground, construction materials, microhabitat, and anything else that might be pertinent. I learned that caracaras make their nests in cabbage palms 97% of the time in Florida (saguaro cactus in Arizona), but could find no real verbiage on the flavor of the palm or its nest. This post seeks to partially rectify that situation. I have seen a couple of dozen caracara nests by now, not very many by any means, but there are consistencies in what I am seeing that might benefit others. At any rate, the information in this post is more than I could easily find on the internet elsewhere.
Most nest palms are within small groups of one to eight palms and are rarely at the edges of or within large hammocks. It is believed this enables caracaras to have almost unrestricted vision all around the nest tree so that they may better keep a vigil for predators and prey. The typical nest tree is close to several good perches, preferably snags (dead trees), but they will sit in the canopies of living trees if acceptable snags are in short supply. The nest tree is often close to a freshwater pond or marsh so that adults do not have to travel far to get food for mates and young. This photo shows a typical nest site, with the nest being in one of three adjacent palms, two more solo palms in the near distance, and a nearby snag and pine with commanding views. The closest palm contains the nest.
The canopy of the tree will often have a single "landing gap" facing a clear flyway that the birds use to enter and exit the nest canopy. Interestingly, the palm frond on which it perches does not suddenly shake when an adult launches itself from the palm canopy, Even when I watched the nest tree intently, a caracara will seem to suddenly appear out of thin air from behind the tree rather than leave a shaking limb in its wake. This may be a way to avoid giving away its nest to a predator.
The nest tree will not have petiole “boots” still in place from the ground up, presumably so that snakes and other predators cannot easily ascend and attack eggs and nestlings. The tree will have one to several lianas (woody vines), but they will not bush out along the trunk and create a ladder for interlopers. The net effect is a smooth and clean trunk that frustrates nest predators .The tree will be old enough that it has several year’s worth of dried inflorescences still firmly attached and emerging beyond the canopy. Lianas climb the inflorescences and “bush out,” thus creating a “rat’s nest” of tangled vegetation that is large and dense enough that a medium-sized bird nest cannot be easily seen from the ground. Caracaras will tamp down the tangle to make it flat on top and will then augment the platform with dried vines and cabbage palm “socks.”
What are cabbage palm boots and socks? Look at the picture below of a relatively young cabbage palm, noticing on the ground the three Y-shaped thingies and the mass of light brown fibrous material. The Y-shaped boot is the basal part of the palm frond petiole (leaf “stem”) that attaches the palm leaf to the trunk. A few months after a cabbage palm leaf dies it will break off a short distance away from the trunk leaving the boot firmly attached to the tree. When looking at a bunch of cabbage palms, you will often notice that some palms retain their boots and others do not. Evidently, the palms must reach some threshold height or age, or something, before the boots drop off. The fibrous material is produced along the margins of the boots, but by the time the boot falls off the tree, the fibrous material has long since rotted away. For the caracara to use these fibers, it must pick at them when they are alive and tough, near the top of the tree.
Florida Crackers have been calling Y-shaped frond bases “boots” for a long time. I may have independently invented the use of the word “socks” to apply to the basal fibers (socks go with boots, right?), but it’s such an obvious connection that I bet it’s been made before.
In addition to the vines and flower stalks, caracaras weave slender, supple pieces of vegetation and plastic into the nest. The vegetation used seems to be primarily greenbriar (Smilax spp.) stems, but only the very thin, wiry ones with tiny spines. They will also use grasses and stems from other vine species. One nest examined contained black plastic strapping and orange plastic packing twine, and another nest had a piece of red plastic surveyors flagging waving in the wind. In all the cases I have seen, however, nest materials were slender and supple rather than stout and stiff.
Especially interesting is that the adults weave a tightly packed pad of palm sock material appx 10 to 12 inches in diameter and 3 to 5 inches thick into the top-center of the nest. This not only provides a soft, insulating substrate for family, but also is gentler on the bare bottoms of incubating adults and nestlings. This pic below shows a downed nest that gives you some idea of the overall size, 2.5 – 3 feet in diameter, plus the sock pad (broken up).
As the palm grows upward and its lower fronds die and fall off, attached lower portions of large nests will break away and fall to the ground. If a nest is used every year for several years, it will look like a column of debris extending vertically through the canopy fronds. Sometimes the column will be 4 - 4 feet in height, but most nests I have seen are not so fully-developed. I imagine that as the nest ages and settles, mold and parasites might make it uninhabitable. This is a likely explanation of why they use a nest for only a year or two, and move around among several nests over the years.
The tree may have a very few bird droppings under it because they release most of their feces elsewhere. Favored snags and the ground underneath are sometimes spattered with droppings and may the have remains of food items scattered about. Armored catfish, cattle egret feathers, and miscellaneous bones are frequently found. Oddly, this caracara eggshell was found under an active nest. Ordinarily an adult would remove the egg from the area of the nest.
The caracara is careful in other ways to keep the secret of the nest location. The male and female do not enter the nest at the same time, so predators don’t get a quick second look. They tend to enter the nest fast and from a cryptic route. They will rarely enter a nest if they know someone is watching. At day’s end, they have a neat trick or two to fool you. If both are out of the nest but close by appx an hour before sunset and well before nocturnal predators some out to hunt, the male will suddenly leap off his perch and fly in plain sight only a few dozens of feet from you and tear then outta there fast! You will get excited and jump up and run to follow it with binoculars to see where it goes, but it quickly flies behind a tree line and is lost from view. You look back to the perch to see what the female is doing, but she is gone, vanished. You realize you’ve been had. She snuck into the nest while the male decoyed you away! Now the male needs to get into the nest without being seen. He returns, and if you are still there and he sees you, he has another trick up his sleeve. He waits until about 10 to 15 minutes after official sunset, when there is just enough light to fly by, and then he suddenly launches and flies off again. Again, you jump up and run to where you can get a clearer view of his flight path, but he rounds a corner and is gone. You don’t realize it until it is too late that he is flying a circuitous route to land on the other side of the nest tree canopy.
How do I, the professional wildlifer overcome these diabolical stratagems? Stay tuned, because evolution has prepared me, too…
Most nest palms are within small groups of one to eight palms and are rarely at the edges of or within large hammocks. It is believed this enables caracaras to have almost unrestricted vision all around the nest tree so that they may better keep a vigil for predators and prey. The typical nest tree is close to several good perches, preferably snags (dead trees), but they will sit in the canopies of living trees if acceptable snags are in short supply. The nest tree is often close to a freshwater pond or marsh so that adults do not have to travel far to get food for mates and young. This photo shows a typical nest site, with the nest being in one of three adjacent palms, two more solo palms in the near distance, and a nearby snag and pine with commanding views. The closest palm contains the nest.
The canopy of the tree will often have a single "landing gap" facing a clear flyway that the birds use to enter and exit the nest canopy. Interestingly, the palm frond on which it perches does not suddenly shake when an adult launches itself from the palm canopy, Even when I watched the nest tree intently, a caracara will seem to suddenly appear out of thin air from behind the tree rather than leave a shaking limb in its wake. This may be a way to avoid giving away its nest to a predator.
The nest tree will not have petiole “boots” still in place from the ground up, presumably so that snakes and other predators cannot easily ascend and attack eggs and nestlings. The tree will have one to several lianas (woody vines), but they will not bush out along the trunk and create a ladder for interlopers. The net effect is a smooth and clean trunk that frustrates nest predators .The tree will be old enough that it has several year’s worth of dried inflorescences still firmly attached and emerging beyond the canopy. Lianas climb the inflorescences and “bush out,” thus creating a “rat’s nest” of tangled vegetation that is large and dense enough that a medium-sized bird nest cannot be easily seen from the ground. Caracaras will tamp down the tangle to make it flat on top and will then augment the platform with dried vines and cabbage palm “socks.”
What are cabbage palm boots and socks? Look at the picture below of a relatively young cabbage palm, noticing on the ground the three Y-shaped thingies and the mass of light brown fibrous material. The Y-shaped boot is the basal part of the palm frond petiole (leaf “stem”) that attaches the palm leaf to the trunk. A few months after a cabbage palm leaf dies it will break off a short distance away from the trunk leaving the boot firmly attached to the tree. When looking at a bunch of cabbage palms, you will often notice that some palms retain their boots and others do not. Evidently, the palms must reach some threshold height or age, or something, before the boots drop off. The fibrous material is produced along the margins of the boots, but by the time the boot falls off the tree, the fibrous material has long since rotted away. For the caracara to use these fibers, it must pick at them when they are alive and tough, near the top of the tree.
Florida Crackers have been calling Y-shaped frond bases “boots” for a long time. I may have independently invented the use of the word “socks” to apply to the basal fibers (socks go with boots, right?), but it’s such an obvious connection that I bet it’s been made before.
In addition to the vines and flower stalks, caracaras weave slender, supple pieces of vegetation and plastic into the nest. The vegetation used seems to be primarily greenbriar (Smilax spp.) stems, but only the very thin, wiry ones with tiny spines. They will also use grasses and stems from other vine species. One nest examined contained black plastic strapping and orange plastic packing twine, and another nest had a piece of red plastic surveyors flagging waving in the wind. In all the cases I have seen, however, nest materials were slender and supple rather than stout and stiff.
Especially interesting is that the adults weave a tightly packed pad of palm sock material appx 10 to 12 inches in diameter and 3 to 5 inches thick into the top-center of the nest. This not only provides a soft, insulating substrate for family, but also is gentler on the bare bottoms of incubating adults and nestlings. This pic below shows a downed nest that gives you some idea of the overall size, 2.5 – 3 feet in diameter, plus the sock pad (broken up).
As the palm grows upward and its lower fronds die and fall off, attached lower portions of large nests will break away and fall to the ground. If a nest is used every year for several years, it will look like a column of debris extending vertically through the canopy fronds. Sometimes the column will be 4 - 4 feet in height, but most nests I have seen are not so fully-developed. I imagine that as the nest ages and settles, mold and parasites might make it uninhabitable. This is a likely explanation of why they use a nest for only a year or two, and move around among several nests over the years.
The tree may have a very few bird droppings under it because they release most of their feces elsewhere. Favored snags and the ground underneath are sometimes spattered with droppings and may the have remains of food items scattered about. Armored catfish, cattle egret feathers, and miscellaneous bones are frequently found. Oddly, this caracara eggshell was found under an active nest. Ordinarily an adult would remove the egg from the area of the nest.
The caracara is careful in other ways to keep the secret of the nest location. The male and female do not enter the nest at the same time, so predators don’t get a quick second look. They tend to enter the nest fast and from a cryptic route. They will rarely enter a nest if they know someone is watching. At day’s end, they have a neat trick or two to fool you. If both are out of the nest but close by appx an hour before sunset and well before nocturnal predators some out to hunt, the male will suddenly leap off his perch and fly in plain sight only a few dozens of feet from you and tear then outta there fast! You will get excited and jump up and run to follow it with binoculars to see where it goes, but it quickly flies behind a tree line and is lost from view. You look back to the perch to see what the female is doing, but she is gone, vanished. You realize you’ve been had. She snuck into the nest while the male decoyed you away! Now the male needs to get into the nest without being seen. He returns, and if you are still there and he sees you, he has another trick up his sleeve. He waits until about 10 to 15 minutes after official sunset, when there is just enough light to fly by, and then he suddenly launches and flies off again. Again, you jump up and run to where you can get a clearer view of his flight path, but he rounds a corner and is gone. You don’t realize it until it is too late that he is flying a circuitous route to land on the other side of the nest tree canopy.
How do I, the professional wildlifer overcome these diabolical stratagems? Stay tuned, because evolution has prepared me, too…
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