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Die hard kite!

In August 2023 we began an important step for our Hook-billed Kite Project in Costa Rica: capturing and banding individuals.  We had our nets and kites feeding in our study site, but would we be able to catch any?


It turns out the answer to this question was a definitive yes as we successfully captured several individuals in our first attempts, and for this write-up we will be focusing on one individual in particular who we named Rosa, banded with a pink band on her right leg in August.


During later visits to our study site we were able to keep track of Rosa by spotting her sporting the pink band on her right leg, noting the coordinates of her location so we could eventually understand some basic aspects of her ecology, such as how much territory does one individual need to survive?


In October we wanted to up our game with the HBKIs and we purchased a special GSM/GPS transmitter which takes precise locations at specific times,uploads the data over cellular connection and it has a solar panel which in theory should allow this unit to work for an extended period; a fantastic tool if we were able to deploy it on a bird.  In late October during one of our netting sessions we caught several birds and among them we recaptured Rosa and she became the chosen one to carry this special transmitter on her back.


During the following days we began receiving data on Rosa’s location and it was very evident she was hunting for the most part in the chayote fields and resting and sleeping in an adjacent grove of trees behind a house.  We also noticed she had a particular liking for slugs! This was all very exciting to watch as the data came in, anxiously waiting for her daily check-in at 11:00 a.m. to see where she was.  However, we began noticing something slightly worrying: the transmitter’s battery was not charging properly and when we tracked her down to try and decipher what was going on we immediately noticed how one feather on her upper back was covering the solar panel almost entirely, not allowing the unit to charge correctly.  As the days went on we watched how the battery gradually depleted itself which made us worry, not so much for the transmitter, rather for Rosa, having to carry it around uselessly.




Rosa feeding on a slug in chayote fields.


We now had a new mission: recapture Rosa!  The transmitter had sent us a substantial amount of data already, giving us an idea of her daily routine, which should have been a great advantage for us. None-the-less it seemed as if Rosa already knew what we were up to and recognized us, our vehicle, the net poles… Time and time again, no matter how we attempted to outwit her, she avoided the nets every single time, coming very close at times, but evidently avoiding our setup. It almost seemed she was taunting us! Eventually we gave-up and continued with our usual field work, telling ourselves we might just get lucky and catch her without trying. Roughly every two weeks Rosa’s transmitter would accumulate enough charge to turn back on for a couple days and send a bit more data and this was our accepted reality.



Rosa flying away from the nets and us.


One morning as we were working in a nearby chayote field we caught several HBKIs and much to our surprise one of them was banded with a pink band on her right leg! After taking her measurements and recording all the data we snipped off her harness and took the transmitter off and all three of us seemed very relieved.  We released Rosa and planned to continue learning about her home range by looking for her pink band. 



Rosa with transmitter. Detail of left wing. Dirty talons from foraging in chayote fields.


During our regular visits to the fields we would frequently spot her and take note of her coordinates to add to the map, but one afternoon we noticed a male flying very decidedly into Rosa’s grove of trees which seemed a bit suspicious to us. Just by chance, the owners of the property were standing outside and invited us in after we explained what we were doing staring into their property with binoculars and a spotting scope! After a few minutes of watching the male he broke a twig from one tree and flew to another just over our heads, and low and behold, there was a nest! The most exciting part about this was that he was not alone, there was a female laying in the nest and she had a pink band on her right leg!


Rosa was now nesting, but we could not see if they had eggs or chicks at this point. During nest inspection over the following days we finally noticed a little white fluff ball sitting in the flimsy nest and both parents busily bringing it food.



Rosa's chick in the nest.



Being a single chick it was growing very quickly and it had lost most of its downy white feathers so we knew fledging time was getting closer, and we began carrying our banding equipment with us during the nest inspections just in case we had the enormous fortune of finding the fledgling in an accessible place. This is exactly what happened in late May 2024 when we noticed the chick had fledged and was perching very low in a tree just outside the house, so we carefully caught it, banded it, took the important measurements and released it again. Fledging is a dangerous part of a young bird’s life and we were uncertain if we would ever see it again, but if we did we would know because it has orange over metal on its right leg.



Rosa's chick recently fledged and banded.


For various reasons we were not able to follow-up on the whereabouts of the fledgling who we called Ruth (that is the name of the property where it was born). Eleven days later we finally had a chance to look for it and we started by visiting Rosa’s favorite feeding grounds and right away we found her perching atop a post over the chayote plants. This was hopeful, but no fledgling was in sight. We waited a little longer as the rain came near and suddenly we heard a faint vocalization, but one we know all too well, and after some searching we found Ruth perching in the dense foliage of some taller trees! We have been keeping an eye on Rosa and Ruth to learn more about the post-fledging period and two weeks after fledging Ruth has started hunting on her own, but continues to be fed by her mother.



Rosa feeding Ruth.

As you can notice, Rosa took her band off recently... to be continued.


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