This is according to a joint study by Tel Aviv University and UCLA. The study included 142 eagles in Israel (biblical eagle, Gyps fulvus) and this is one of the few studies that sheds light on the behavioral changes with the aging of animals in the wild
A new study, and the first of its kind, by Tel Aviv University revealed that, similar to humans, the movement habits and social relationships of the eagles also change with age: at young ages, they skip between lodging sites almost every night, and "spend a lot of time with friends." At the age of majority, half of the time they sleep in the permanent accommodation site ('at home') and the rest of the time in other sites, while in old age they reduce social ties and prefer to stay 'at home'. The study included 142 eagles in Israel (biblical eagle, Gyps fulvus) and this is one of the few studies that sheds light on the behavioral changes with the aging of animals in the wild.
The research was conducted under the leadership of Dr. Marta Aksio, as part of a post-doctorate that she conducted in the laboratory of Dr. Orr Spiegel from the School of Zoology at Tel Aviv University and in collaboration with Prof. Noa Pinter Wellman from the University of California at Los Angeles (UCLA) and several other researchers. The study was published in the prestigious journal PNAS.
Dr. Spiegel explains: "Eagles are a locally endangered species in Israel. There are about 200 individuals left in Israel in total, and they are being monitored to know how to preserve them in the best possible way. But in this study we thought what else could be done with the impressive database we have accumulated over the years, and we thought it would be interesting to see how eagles age. It is often very difficult to follow the same individuals in the wild over many years, and the transmitters we use to monitor the population provided us with a rare glimpse into the aging of eagles in particular and of animals in general."
As part of the study, the researchers used the database accumulated over 15 years from GPS devices attached to 142 eagles, for periods of up to 12 years. The eagle is a social bird, and it sleeps in roosts on cliffs. The researchers cross-referenced the eagles' ages with the GPS data on their roosting sites - and found that as they got older, they preferred to stay at the same roosting site.
Dr. Spiegel: "It turns out that aging eagles behave a bit like humans and are more inclined to stay at home. At young ages the eagles like to check out new sites and move between places, so for example the chance that a young eagle will return to sleep at the same site two nights in a row is small. When they reach adulthood at the age of five it stabilizes, and as adults they spend 50% of the nights at the same site and 50% of the nights at other sites. When they are old, from the age of 10 onwards, they no longer have the energy for "entertainment" and will return again and again to the same site. And, when an adult eagle does change sites, it does so in a predictable way: for example, one night in Ein Avdat, one night in the small crater and one night in Nahal Golhan - and God forbid returns in a fixed order. Of course, it could be argued that the old move less, not because they are old, but because they don't take risks in the first place - and that's why they reached their extreme age. But here we are talking about the exact same details: the one who was an adventurer at the age of 5 gets tired when he reaches the age of 10."
According to Dr. Spiegel, the fascinating findings on the aging of birds also have very practical implications regarding the efforts to preserve them in the wild. "The new research can help us better protect the Teva eagles' roosting sites. Moreover, we see that old eagles have less social connections, and this can help us fight poisoning. These transmitters are connected to the system, which sends an alert to the Nature and Parks Authority and to us on the phone if the eagle does not move or if it has landed in a dangerous place - that is, if there is a danger that it has been poisoned, which unfortunately happens very frequently. The danger is that the eagle will see a goat carcass in the field and descend on it, not knowing that the farmer poisoned the carcass to kill stray dogs. But this is a social bird, and the eagle did not come down alone. In this way, up to dozens of eagles may die at once. It will help us a lot to understand how wide the poisoned eagle's social circle is, in order to reduce the damage."
It should be noted that eagles play an important ecological role in disposing of carcasses, and studies have shown that the extinction of eagles ultimately costs human lives due to an increase in diseases such as rabies. In India, for example, a recently published study shows that the extinction of eagles due to poisoning resulted in an increase in the mortality of half a million people over five years.
A new study, and the first of its kind, by Tel Aviv University revealed that, similar to humans, the movement habits and social relationships of the eagles also change with age: at young ages, they skip between lodging sites almost every night, and "spend a lot of time with friends." At the age of majority, half of the time they sleep in the permanent accommodation site ('at home') and the rest of the time in other sites, while in old age they reduce social ties and prefer to stay 'at home'. The study included 142 eagles in Israel (biblical eagle, Gyps fulvus) and this is one of the few studies that sheds light on the behavioral changes with the aging of animals in the wild.
The research was conducted under the leadership of Dr. Marta Aksio, as part of a post-doctorate that she conducted in the laboratory of Dr. Orr Spiegel from the School of Zoology at Tel Aviv University and in collaboration with Prof. Noa Pinter Wellman from the University of California at Los Angeles (UCLA) and several other researchers. The study was published in the prestigious journal PNAS.
Dr. Spiegel explains: "Eagles are a locally endangered species in Israel. There are about 200 individuals left in Israel in total, and they are being monitored to know how to preserve them in the best possible way. But in this study we thought what else could be done with the impressive database we have accumulated over the years, and we thought it would be interesting to see how eagles age. It is often very difficult to follow the same individuals in the wild over many years, and the transmitters we use to monitor the population provided us with a rare glimpse into the aging of eagles in particular and of animals in general."
As part of the study, the researchers used the database accumulated over 15 years from GPS devices attached to 142 eagles, for periods of up to 12 years. The eagle is a social bird, and it sleeps in roosts on cliffs. The researchers cross-referenced the eagles' ages with the GPS data on their roosting sites - and found that as they got older, they preferred to stay at the same roosting site.
Dr. Spiegel: "It turns out that aging eagles behave a bit like humans and are more inclined to stay at home. At young ages the eagles like to check out new sites and move between places, so for example the chance that a young eagle will return to sleep at the same site two nights in a row is small. When they reach adulthood at the age of five it stabilizes, and as adults they spend 50% of the nights at the same site and 50% of the nights at other sites. When they are old, from the age of 10 onwards, they no longer have the energy for "entertainment" and will return again and again to the same site. And, when an adult eagle does change sites, it does so in a predictable way: for example, one night in Ein Avdat, one night in the small crater and one night in Nahal Golhan - and God forbid returns in a fixed order. Of course, it could be argued that the old move less, not because they are old, but because they don't take risks in the first place - and that's why they reached their extreme age. But here we are talking about the exact same details: the one who was an adventurer at the age of 5 gets tired when he reaches the age of 10."
According to Dr. Spiegel, the fascinating findings on the aging of birds also have very practical implications regarding the efforts to preserve them in the wild. "The new research can help us better protect the Teva eagles' roosting sites. Moreover, we see that old eagles have less social connections, and this can help us fight poisoning. These transmitters are connected to the system, which sends an alert to the Nature and Parks Authority and to us on the phone if the eagle does not move or if it has landed in a dangerous place - that is, if there is a danger that it has been poisoned, which unfortunately happens very frequently. The danger is that the eagle will see a goat carcass in the field and descend on it, not knowing that the farmer poisoned the carcass to kill stray dogs. But this is a social bird, and the eagle did not come down alone. In this way, up to dozens of eagles may die at once. It will help us a lot to understand how wide the poisoned eagle's social circle is, in order to reduce the damage."
It should be noted that eagles play an important ecological role in disposing of carcasses, and studies have shown that the extinction of eagles ultimately costs human lives due to an increase in diseases such as rabies. In India, for example, a recently published study shows that the extinction of eagles due to poisoning resulted in an increase in the mortality of half a million people over five years.
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