The Chinijo Archipelago, located in the north of the island of Lanzarote, is the most important natural area in the Canary Islands. This population makes up the westernmost and southernmost population of the entire breeding range of the species. Nuestro equipo ha monitorizado un total de nidos en Alegranza. La productividad ha sido de 1. Desafortunadamente, el ejemplar fue encontrado muerto sin que pudiesen determinarse las causas. Our team has monitored a total of nests on Alegranza.
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The Chinijo Archipelago, located in the north of the island of Lanzarote, is the most important natural area in the Canary Islands. This population makes up the westernmost and southernmost population of the entire breeding range of the species.
Nuestro equipo ha monitorizado un total de nidos en Alegranza. La productividad ha sido de 1. Desafortunadamente, el ejemplar fue encontrado muerto sin que pudiesen determinarse las causas. Our team has monitored a total of nests on Alegranza. The productivity reached 1. Noticeably, one of these pairs managed to raise 4 fledglings. Although the laying of 4 eggs is not so rare, to raise 4 fledglings turns out to be quite uncommon in this population.
Since the beginning of the project, only one such case had been registered, which tool place in This year we have ringed a total of fledglings and made a total of visual recaptures of individuals ringed by our team in previous years. Among these readings, we have been able verify the presence of a high number of falcons born in and Both years were quite good for the Canarian population of the species in terms of food availability and productivity, which has undoubtedly influenced the high survival rates of these cohorts.
Many of these individuals have been recruited into the breeding fraction of the population, which experiences a high turnover rate mainly due to instability in resource availability and associated mortality. We were also able to retrieve a GPS-datalogger that was mounted in a female falcon in Unfortunately, the bird was found dead for unknown reasons. Although this is a sad finding, we hope to recover all the information stored in the datalogger about the migration routes and wintering areas of this falcon.
There is a dam on Alegranza that was built on the second half of the XIX century, when the island was still habited by humans, to collect rainwater. As it was for humans, the availability of fresh water is a limiting factor on a practically desert island such as Alegranza. With the passage of time and the relentless erosion of the land, the dam is nowadays filled with sediments. Even so, the dam continues to accumulate water after the rains, and today this pond is the only source of fresh water in all the uninhabited islands of the Chinijo archipelago.
Almost all the bird species that inhabit or nest on Alegranza and nearby islets go to this enclave daily to drink and bath, even during the night. In total, we have identified 10 species that habitually use the pond, including Falconiformes, Accipitriformes, Strigiformes, Charadriiformes y Passeriformes, in addition to a large number of birds that use this resource as a stop over during their migration. It is also used by endemic lizards, as well as by introduced amphibians and mammals.
Our team also uses this dam regularly as part of the monitoring, as it is a key place to read the plastic rings of the falcons and make behavioral observations. El primero de ellos fue localizado el 31 de julio en Arrecife Lanzarote , y se trataba de un ejemplar macho anillado como pollo en Alegranza en El segundo ejemplar fue localizado el 19 de agosto en Morro Jable Fuerteventura , y este caso se trataba de una hembra joven sin anillar, por lo que no podemos confirmar su procedencia.
Like every year, we devoted the first weeks to locate the active territories and to identify the individuals by reading their plastic rings. In so doing we determined that many individuals born in and are present on the island, and some of them have been recruited into the breeding population.
So far, we have located about breeding territories, a number similar to that found in previous years. However, the areas occupied have notably changed; some abandoned areas have been recolonized while others areas not occupied so far have been colonized.
Despite the seemingly high proportion of new recruits we still found a good number of old individuals on their habitual territories. Moreover, out of the 19 individuals that left Alegranza with a GPS-logger in 9 tagged last year, 10 in the years before , 10 have made it back from their spectacular migration to Madagascar. We have already been able to download much of the tracking data collected by these birds and look forward to analyze their migratory behavior in more detail after the field season.
Unfortunately, like every year, there is also bad news for the falcons. Until now, two injured individuals have been found on the neighboring islands of Lanzarote and Fuerteventura. One of them was found on the 31 st July in Arrecife Lanzarote. It was a male falcon, which was ringed as a fledgling on Alegranza in Regrettably, this male died soon after being found.
We are still waiting for the results of the necropsy and toxicological analyses to determine the cause of death. The second individual was found on the 19 th August in Morro Jable Fuerteventura. This female was extremely weak, and was immediately admitted to a specialized clinic where she is receiving the best care to, hopefully, be released as soon as possible. Se trataba de una hembra nacida en Alegranza y anillada como pollo el 17 de septiembre de On November 23, Alexis Cuviller observed a weakened individual posed on the ground.
Only two days later, the individual was found dead without apparent injury. It was a female bird born on Alegranza and ringed as a fledgling on September 17 The presence of the rings both metal and plastic ring with two alphanumeric digits was what confirmed this interesting, though sad observation. The proximity of the island where it was found to Madagascar, as well as the date of the observation, suggests that the individual was in migration towards its wintering quarters.
This is the first observation of the species in this area. Already at the beginning of the breeding season, we noticed the absence of several known adult individuals and the presence of numerous young birds either replacing one of these adults, or engaging on their first breeding attempt as a new young couple.
In , for example, the mean clutch size was 2. The productivity, i. This figure is also lower than that recorded in , which was 2. Overall, we ringed individuals, mostly fledglings born in Alegranza. In total, we have made visual recaptures of falcons ringed by our team in previous years.
Of these, 12 correspond to birds born in on the islets of Chinijo Archipelago. Thanks to the plastic rings, we were able to detect a rather singular case. It happened to be a male who was simultaneously breeding in two different nests with two different females. The male devoted his time in hunting to feed both females and relieve them in the hard task of incubation.
But sometimes, being too ambitious can be a bad business. The distance between both nest sites was considerable and one of those failed at the end of August. The other nest of the bigamous male is still active. In we witnessed a similar case, but in this occasion, both nests of the same male were only ca.
One of the females had been his mate for several years, although they never raised any chick. The other female was a recent widow from a neighbor nest. The male copulated with both females and hunted to feed them in a rather constant and simultaneous way. However, only one of the females the widow was able to breed successfully. Se trata de un macho que se encontraba regentando dos nidos con dos hembras diferentes a la vez. Pero como suele decirse, el que mucho abarca… poco aprieta.
Saltar al contenido. El viento es el elemento principal alrededor del cual gira toda la vida de los halcones de Eleonor en Canarias. The trade winds that blow during the summer and early autumn allow the arrival of small birds to the Canary Islands, making them deviate from their route during their post-nuptial migration.
Therefore, the presence of strong NE winds is a good sign that predicts the arrival of food. This video shows the installation of a relay to receive data from falcons equipped with GPS-dataloggers on any given day, a day when the trade winds were blowing strongly. Entradas antiguas.
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