21-07-2023
A recent study of the goshawk population in the Serralada Litoral Park indicates that the population remains apparently stable
Specimen of goshawk seen in the Parc de la Serralada Litoral. Author: Francesc Xavier Macià Valverde
The results of the study carried out in 2022 to update the situation of the goshawk (Accipiter gentilis) population in the Serralada Litoral Park, indicate that the population of this raptor remains stable in the Park. However, low reproductive rate, which would not exceed 25% in the best case scenario, are worrying. The study is available in the collective catalog of the documentation centers of the Natural Parks Network.
The document, entitled Inventory of the goshawk (Accipiter gentilis) population in the Serralada Litoral Park - Year 2022, has been prepared by Santi Mañosa and Rifé and Javier Oliver Alejos, researchers at the Department of Evolutionary Biology, Ecology and Environmental Sciences, Biodiversity Research Institute of the University of Barcelona (IRBio-UB).
Based on the existing information corresponding to the period 2010-2016, the breeding sectors or areas occupied by the goshawk in the Park and bordering areas during the breeding season of this species (with a reference surface of about 7,500 hectares) have been visited again in 2022 to determine if they are still active.
Thus, following the most favorable calendar and times for the detection of goshawks, the fourteen known nesting areas were visited, although it was not an exhaustive census with the prospecting of new territories, nor was it possible to follow the reproductive success, beyond the three visits that were made to each known nest stand. If no activity of the goshawk was detected during the field visits, its claim was broadcast with a megaphone waiting for a response, especially from the male. The visual search for signs of the presence of the species was also taken into account, such as traces of prey, recent feces and/or feathers.
An apparently stable population
The data indicates that signs of safe presence were found in 8-9 sectors, a fact that seems to indicate, with due caution, that the starling population would remain stable in the Park with respect to the data known so far (corresponding to the period 2010-2016), with a density of 11-13 active pairs/100 km2, a relatively high figure for this species.
Conversely, the worrying aspect of the results is the low reproductive success. Of the 8-9 sectors occupied, the goshawk has only had reproductive success in 1 or 2, which corresponds to 25% at best, an extremely low value for this species.
The study, apart from establishing the basis for carrying out a census and exhaustive monitoring of the pairs of starlings present in the Park, suggests continuing the monitoring to rule out that it is a structural problem and to follow and analyze in more detail the possible factors that, beyond the possibility that it is a particularly bad year, may be negatively affecting the reproduction of this species in an overcrowded area such as the Parc de la Serralada Litoral.
Finally, the work points out that occupied forest stands should be subject to special protection and management to prevent avoidable reproductive failures and that an inventory should be made of all the stands potentially susceptible to being used. The horizon of a standardized network work in the set of natural spaces of the Natural Parks Network regarding the monitoring of nests will perhaps provide interesting data with reference to this problem.
One of the positive aspects related to the methodology has been the preparation of detailed information sheets for each known nest, in which an outstanding effort has been made in the description of access in order to facilitate the visit to the staff of the Park or to specialists and scholars who may wish to access it in the future in accordance with the conservation objectives of the Park.
In this sense and within the framework of the collaboration agreement of the Catalan Institute of Ornithology (ICO) with the Natural Parks Network, during 2023 the rangers of the Serralada Litoral Park have accompanied specialists from this organization to monitor some of these nests. The aim is to progressively join the monitoring of the Park's raptor nests, in parallel with the work of the specialists which is essential in this group of protected birds.
Youtube channel of the astor
The work is available in the collective catalog of the documentation centers of the Natural Parks Network at this link. For more information about the goshawk, on the Astor Youtube channel of the Parc de la Serralada Litoral you can retrieve numerous videos of the various nestings since 2015 that show the day-to-day life of these birds of prey, whether it is a female restoring the nest or the chicks that have been born in dispute for food. The channel also collects videos of other birds of prey that breed in the Park, for example the Marcen eagle or the evening plover.
Mañosa, S. and Oliver, J. (2023). Inventory of the goshawk population (Accipiter gentilis) in the Serralada Litoral Park - Year 2022. Unpublished report. Serralada Litoral Park-University of Barcelona. Barcelona.
Source of information: Natural Parks Network
Date: 12/07/2023
The results of the study carried out in 2022 to update the situation of the goshawk (Accipiter gentilis) population in the Serralada Litoral Park, indicate that the population of this raptor remains stable in the Park. However, low reproductive rate, which would not exceed 25% in the best case scenario, are worrying. The study is available in the collective catalog of the documentation centers of the Natural Parks Network.
The document, entitled Inventory of the goshawk (Accipiter gentilis) population in the Serralada Litoral Park - Year 2022, has been prepared by Santi Mañosa and Rifé and Javier Oliver Alejos, researchers at the Department of Evolutionary Biology, Ecology and Environmental Sciences, Biodiversity Research Institute of the University of Barcelona (IRBio-UB).
Based on the existing information corresponding to the period 2010-2016, the breeding sectors or areas occupied by the goshawk in the Park and bordering areas during the breeding season of this species (with a reference surface of about 7,500 hectares) have been visited again in 2022 to determine if they are still active.
Thus, following the most favorable calendar and times for the detection of goshawks, the fourteen known nesting areas were visited, although it was not an exhaustive census with the prospecting of new territories, nor was it possible to follow the reproductive success, beyond the three visits that were made to each known nest stand. If no activity of the goshawk was detected during the field visits, its claim was broadcast with a megaphone waiting for a response, especially from the male. The visual search for signs of the presence of the species was also taken into account, such as traces of prey, recent feces and/or feathers.
An apparently stable population
The data indicates that signs of safe presence were found in 8-9 sectors, a fact that seems to indicate, with due caution, that the starling population would remain stable in the Park with respect to the data known so far (corresponding to the period 2010-2016), with a density of 11-13 active pairs/100 km2, a relatively high figure for this species.
Conversely, the worrying aspect of the results is the low reproductive success. Of the 8-9 sectors occupied, the goshawk has only had reproductive success in 1 or 2, which corresponds to 25% at best, an extremely low value for this species.
The study, apart from establishing the basis for carrying out a census and exhaustive monitoring of the pairs of starlings present in the Park, suggests continuing the monitoring to rule out that it is a structural problem and to follow and analyze in more detail the possible factors that, beyond the possibility that it is a particularly bad year, may be negatively affecting the reproduction of this species in an overcrowded area such as the Parc de la Serralada Litoral.
Finally, the work points out that occupied forest stands should be subject to special protection and management to prevent avoidable reproductive failures and that an inventory should be made of all the stands potentially susceptible to being used. The horizon of a standardized network work in the set of natural spaces of the Natural Parks Network regarding the monitoring of nests will perhaps provide interesting data with reference to this problem.
One of the positive aspects related to the methodology has been the preparation of detailed information sheets for each known nest, in which an outstanding effort has been made in the description of access in order to facilitate the visit to the staff of the Park or to specialists and scholars who may wish to access it in the future in accordance with the conservation objectives of the Park.
In this sense and within the framework of the collaboration agreement of the Catalan Institute of Ornithology (ICO) with the Natural Parks Network, during 2023 the rangers of the Serralada Litoral Park have accompanied specialists from this organization to monitor some of these nests. The aim is to progressively join the monitoring of the Park's raptor nests, in parallel with the work of the specialists which is essential in this group of protected birds.
Youtube channel of the astor
The work is available in the collective catalog of the documentation centers of the Natural Parks Network at this link. For more information about the goshawk, on the Astor Youtube channel of the Parc de la Serralada Litoral you can retrieve numerous videos of the various nestings since 2015 that show the day-to-day life of these birds of prey, whether it is a female restoring the nest or the chicks that have been born in dispute for food. The channel also collects videos of other birds of prey that breed in the Park, for example the Marcen eagle or the evening plover.
Mañosa, S. and Oliver, J. (2023). Inventory of the goshawk population (Accipiter gentilis) in the Serralada Litoral Park - Year 2022. Unpublished report. Serralada Litoral Park-University of Barcelona. Barcelona.
Source of information: Natural Parks Network
Date: 12/07/2023