scholarly journals Density dynamics, diet composition and productivity of sparrowhawk Accipiter nisus L. population in central Poland

2018 ◽  
Vol 79 (3) ◽  
pp. 245-251 ◽  
Author(s):  
Jakub Gryz ◽  
Dagny Krauze-Gryz

Abstract Long-term monitoring of raptor populations can serve as a proxy for the evaluation of whole ecosystem health. The aim of the study was to compare the current abundance of the sparrowhawk Accipiter nisus L. with data from past decades. Additionally, we examined the diet of this species in the breeding season and recorded the number of fledglings. The study area encompassed 105 km2 of field and forest mosaic, located in the vicinity of the Rogów village (51°49'17,98''N, 19°53'54,5''E). Forests covered approximately 24% of the area and formed eight individual complexes ranging in size from 65 ha to 1000 ha. In the years 2011–2017, an average of 20.1 sparrowhawk pairs were recorded resulting in a population density of 19.1 pairs per 100 km2 of total area and 8.2/10 km2 of forested area. This is an increase of 26% compared to the years 2001–2003, when only 16 pairs nested in the same study area. Each successful pair of sparrowhawk produced between one and five fledglings with the average being 3.4. Larch Larix spp. and Scots pine Pinus sylvestris L. dominated as nesting trees accounting for 36.9 and 35.9% of nesting sites respectively. The average age of the nesting trees was 31 years and nests were built at an average height of 11.7 m. The sparrowhawk diet was dominated by birds, which amounted to 81.5% of prey items and over 95% of the consumed biomass. Among the birds identified to the species level, the domestic pigeon Columba livia f. domestica Gm. constituted the biggest share in biomass. Further important prey items were starling Sturnus vulgaris L., with 5.6% of prey items and 9.8% of the total biomass, and hawfinch Coccothraustes coccothraustes (L.), with 6.3% of prey items and 7.6% of the total biomass. Sparrowhawks also consumed significant numbers of thrush Turdus spp. that formed in total over 11% of the total consumed biomass. It would appear that the observed population growth was a result of prohibited persecution and the ban on DDT usage in agriculture.

2021 ◽  
Vol 29 (2) ◽  
pp. 177-182
Author(s):  
Naceur Benamor ◽  
Toufik Guetouache ◽  
Farid Bounaceur

Abstract The diet composition of Pharaoh Eagle Owl (Bubo ascalaphus) was investigated in a semiarid area of North-western Algeria. A total of 65 pellets regurgitated by the B. ascalaphus were analysed, 288 food items were composed primarily of mammal remains (4 rodents, 1 bat and insectivore, 93.7%), and 1 bird species (passerine, 6.3%). The most frequent prey among the mammals were rodents (83.3%), which included Mus musculus (59.7%), Meriones shawi (11.1%), Meriones libycus (11.1%) and Jaculus jaculus (1.4%). The rodents were the most important prey items in biomass (91.4%), M. shawi made up to 41.9% of the total biomass. We may conclude that the Pharaoh Eagle Owl relies, in its feeding, very broadly on small mammals, completed by other groups.


2018 ◽  
Vol 26 (2) ◽  
pp. 51-68 ◽  
Author(s):  
Iñigo Zuberogoitia ◽  
Jon Morant ◽  
Iñaki Castillo ◽  
Jose Enrique Martínez ◽  
Gorka Burgos ◽  
...  

Abstract We monitored Peregrine Falcon (Falco peregrinus) population in Bizkaia, Northern Spain, during two decades (1998–2017). Our population increased from 34 to 47 territorial pairs, as did other European populations until the first years of the 21st century, and then declined until 34 territorial pairs in 2017. The combination of catastrophic events (Prestige oil spill), increasing rain in winter and spring, and direct and indirect mortality factors significantly affected incubation onset, productivity and population stability, which in turn could impact on the floater population. Rain in February significantly affected incubation onset, which showed a slight positive trend during the last decade. Juvenile females laid 12 days later than adults, and each adult female started incubation in the same dates every year. However, the proportion of juvenile females did not significantly increase as might have been expected. Moreover, productivity was inversely related to incubation onset dates. Rain in April and May also affected productivity, and combined with short term extreme weather events determined a decreasing productivity during the last decade. Moreover, apart from human persecution (which caused 40.30% of the known deaths of Peregrines), we found 18 cases of breeders affected by infectious diseases, also related to weather. The combined effects of these factors, and the low availability of adequate nesting sites, negatively affected (i) territorial populations, (ii) productivity, and (iii) floater population, which in turn also determined territorial population and productivity.


2019 ◽  
Vol 12 ◽  
pp. 194008291983183 ◽  
Author(s):  
Juan Sebastián Restrepo-Cardona ◽  
César Márquez ◽  
María Ángela Echeverry-Galvis ◽  
Félix Hernán Vargas ◽  
Diana M. Sánchez-Bellaizá ◽  
...  

In anthropogenically transformed habitats, some birds of prey feed on domestic animals, triggering conflict between people and predators. To manage this conflict, it is important to understand the ecological circumstances associated with the predation of domestic animals. We studied variation in the diet of the endangered Black-and-chestnut Eagle ( Spizaetus isidori) in four different Andean landscapes in Colombia. We analyzed 261 prey items brought to five S. isidori nests during the period when the nestlings were being raised. Domestic fowl are relatively frequent prey in the diet of S. isidori in three of the four localities studied (frequency: 9.3%–36%), representing 12.2% to 37.1% of the total biomass of prey consumed. In terms of biomass, in Ciudad Bolívar, Jardín, and Campohermoso, the sites with the greatest forest cover, mammals were the most important prey in the diet of S. isidori, while in Gachalá, the most deforested site, domestic fowl were the most important prey. We recommend that forest cover be maintained and increased to provide habitat for wild prey in the breeding territories of S. isidori using the landscape management tools best suited to the specific socioecological contexts of this eagle’s territories. We also suggest that the management of domestic fowl under controlled conditions or the use of some deterrent be examined as strategies to mitigate or prevent conflict between people and S. isidori. Socioecological research and educational programs should be carried out to increase the public’s understanding of this eagle and its benefits to the ecosystem.


Author(s):  
Barbara S. Minsker ◽  
Charles Davis ◽  
David Dougherty ◽  
Gus Williams

Author(s):  
Robert Klinck ◽  
Ben Bradshaw ◽  
Ruby Sandy ◽  
Silas Nabinacaboo ◽  
Mannie Mameanskum ◽  
...  

The Naskapi Nation of Kawawachikamach is an Aboriginal community located in northern Quebec near the Labrador Border. Given the region’s rich iron deposits, the Naskapi Nation has considerable experience with major mineral development, first in the 1950s to the 1980s, and again in the past decade as companies implement plans for further extraction. This has raised concerns regarding a range of environmental and socio-economic impacts that may be caused by renewed development. These concerns have led to an interest among the Naskapi to develop a means to track community well-being over time using indicators of their own design. Exemplifying community-engaged research, this paper describes the beginning development of such a tool in fall 2012—the creation of a baseline of community well-being against which mining-induced change can be identified. Its development owes much to the remarkable and sustained contribution of many key members of the Naskapi Nation. If on-going surveying is completed based on the chosen indicators, the Nation will be better positioned to recognize shifts in its well-being and to communicate these shifts to its partners. In addition, long-term monitoring will allow the Naskapi Nation to contribute to more universal understanding of the impacts of mining for Indigenous peoples.


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