scholarly journals Diet specialization in an insular population of coastal Peregrine Falcons

2021 ◽  
Author(s):  
Luke J. Sutton ◽  
Sebastian W. Loram
Keyword(s):  
Prey Species ◽  
Columba Livia ◽  
Feeding Strategies ◽  
Generalist Predators ◽  
Herring Gull ◽  
Domestic Pigeon ◽  
Diet Specialization ◽  
Dietary Breadth ◽  
Peregrine Falcons ◽  
Manx Shearwater

AbstractIndividual diet specialization is known to occur in populations of generalist predators, where specific individuals develop specialist feeding strategies. Diet specialization has been reported in many raptor species, and it may be an important driver of intraspecific population structure. Here, we quantify the diet of five breeding pairs of Peregrine Falcons Falco peregrinus from an offshore island determined from prey remains collected over four breeding seasons. Three prey species accounted for 69.8 % of total prey frequency, with Manx Shearwater Puffinus puffinus the primary prey accounting for 47.3 % by frequency and 40.8 % by biomass. Herring Gull Larus argentatus was the second most important prey species by frequency (13.8 %) and biomass (29.8 %) followed by Domestic Pigeon Columba livia (frequency = 8.7 %, biomass = 7.0 %). Predation frequency on specific prey groups varied substantially between breeding pairs and months. Two pairs specialized on Manx Shearwater, one pair specialized on Herring Gull and Manx Shearwater, with the remaining two pairs having a relatively generalist diet of Manx Shearwaters, Domestic Pigeon and small passerines. Predation on Manx Shearwaters increased throughout the breeding season with a peak in total diet frequency of 63.8 % in July, with a concurrent decrease in Herring Gull predation frequency. Higher percentage of Manx Shearwater in the diet was able to explain 87 % of the variation in a narrower dietary breadth for the Peregrine pairs. Our results suggest individual diet specialization may be important for understanding population density in insular raptor populations.

scholarly journals Spatio-temporal trends in the predation of large gulls by peregrine falcons (Falco peregrinus) in an insular breeding population

2017 ◽  
Vol 11 (1) ◽  
pp. 103-109
Author(s):  
Luke J. Sutton ◽  
Ryan A. Burrell ◽  
Seb Loram
Keyword(s):  
Community Structure ◽  
Temporal Trends ◽  
Trophic Levels ◽  
Generalist Predators ◽  
Unexpected Result ◽  
Ecological Specialization ◽  
Falco Peregrinus ◽  
Diet Specialization ◽  
Herring Gulls ◽  
Peregrine Falcons

Abstract Individual diet specialization occurs in many populations of generalist predators, with specific individuals developing specialist strategies in their feeding behaviour. Intraspecific resource partitioning is hypothesised to be common amongst species in higher trophic levels where competition for resources is intense, and a key driver in breeding success and community structure. Though well-studied in other predators, there is sparse data on ecological specialization in raptors, which are important drivers of community and trophic structure. In this study, the breeding season diet of an insular population of peregrine falcons (Falco peregrinus) was determined from indirect analysis of prey remains collected over three years. An unexpected result was the high proportion of large gulls (Laridae), of the genus Larus, in the diet of two breeding pairs of peregrines. Large gulls made up 18.44% by frequency of total prey recorded and 30.81% by biomass. Herring gulls (Larus argentatus) were the most common large gull prey, with immatures most frequent (67.95%) compared to adults (19.23%). Overall, most gulls predated were immatures (80.77%). Frequency of predation varied between breeding pairs and months, but was consistent over the three years. Most gulls were taken in April (37.17%), followed by May (19.23%), with a smaller peak of immature herring gulls taken in August and September. The pattern of regular predation by peregrines on large gulls is a new observation with important implications for understanding individual diet specialization in raptors, and its effect on bird populations and community structure.

Effects of an introduced, novel prey on diet and reproduction in the diet-specialist European Starling (Sturnus vulgaris)

2019 ◽  
Vol 97 (3) ◽  
pp. 225-231
Author(s):  
T.D. Williams ◽  
A. Cornell ◽  
C. Gillespie ◽  
A. Hura ◽  
M. Serota
Keyword(s):  
Prey Item ◽  
Brood Size ◽  
Natural Experiment ◽  
Prey Species ◽  
Sturnus Vulgaris ◽  
European Starling ◽  
Tarsus Length ◽  
Negative Effects ◽  
Diet Specialization ◽  
Specialized Diet

Diet specialization has important consequences for how individuals or species deal with environmental change that causes changes in availability of prey species. We took advantage of a “natural experiment” — establishment of a commercial insect farm — that introduced a novel prey item, black soldier flies (Hermetia illucens (Linnaeus, 1758)), to the diet-specialist European Starling (Sturnus vulgaris Linnaeus, 1758). We investigated evidence for individual diet specialization (IDS) and the consequences of diet specialization and exploitation of novel prey on breeding productivity. In all 4 years of our study, tipulid larvae were the most common prey item. Soldier flies were not recorded in diets in 2013–2014; however, coincident with the establishment of the commercial insect farming operation, they comprised 22% and 30% of all prey items in the diets of European Starling females and males, respectively, in 2015. There was marked individual variation in use of soldier flies (4%–48% and 2%–70% in females and males, respectively), but we found little evidence of dichotomous IDS, i.e., where only some individuals have a specialized diet. We found no evidence for negative effects of use of soldier flies on breeding productivity: brood size at fledging and chick quality (mass, tarsus length) were independent of the number and proportion (%) of soldier flies returned to the nest.

scholarly journals transatlantic Movement of Domestic PIGEONS Columba livia domestica

2020 ◽  
Vol 24 (04) ◽  
pp. 781-790
Author(s):  
Gabriel Silva Santos ◽  
◽  
Maurício Brandão Vecchi ◽  
Maria Alice Santos Alves
Keyword(s):  
Scientific Literature ◽  
Columba Livia ◽  
Decision Makers ◽  
Flight Performance ◽  
Intermediate Hosts ◽  
Southwest Atlantic ◽  
Domestic Pigeon ◽  
Scientific Databases ◽  
Eastern Brazil ◽  
Domestic Pigeons

Historically, Domestic pigeon (Columba livia domestica Gmelin,1789) (Columbiformes, Columbidae) breeders use the species to promotes race competitions which over the time could select traits to increase the flight performance and spatial orientation capabilities. Although the species has remarkable navigational abilities, it is possible that these birds sometimes become disoriented pushing the individuals to fly off-course and over distances larger than usual. Here we report a Domestic Pigeon ringed in the Canary Islands (Spain) observed in the Abrolhos Archipelago, eastern Brazil, and compiled similar events (N = 5) in the Southwest Atlantic Ocean coast. Our results indicate that these events are largely unnoticed in the scientific literature as most of them were found in non-scientific newspaper and academic conferences, thus, untraceable from scientific databases as Scopus and Google Scholar. As domestic pigeons are possible intermediate hosts of diseases, we encourage the creation of a systematized database of this kind of movements of these birds, including the profile of these vagrants and the circumstances in which these events occur, which can be a basis to be used for scientists and decision makers.

The Comparative Feeding Ecology of Six Species of Shark and Four Species of Ray (Elasmobranchii) In The North-East Atlantic

1996 ◽  
Vol 76 (1) ◽  
pp. 89-106 ◽  
Author(s):  
J.R. Ellis ◽  
M.G. Pawson ◽  
S.E. Shackley
Keyword(s):  
Feeding Ecology ◽  
Stomach Contents ◽  
Generalist Predators ◽  
Dietary Overlap ◽  
East Atlantic ◽  
Dietary Breadth ◽  
North East ◽  
The North ◽  
North Eastern ◽  
Commercial Species

The stomach contents of ten species of elasmobranch from the north-eastern Atlantic indicate that most are generalist predators, eating a variety of polychaetes, molluscs, crustaceans and teleosts. Two species, Mustelus asterias and Squatina scjuatina were found to be specialist feeders, consuming portunid crabs and pleuronectids, respectively. Measures for both dietary breadth and dietary overlap are given and the implications of elasmobranch predation on the prey communities and on commercial species are discussed.

scholarly journals Eastern Coyotes (Canis latrans var.) consuming large ungulates in a multi-ungulate system

2020 ◽  
Vol 134 (1) ◽  
pp. 45-51
Author(s):  
Juliana Balluffi-Fry ◽  
Liane B. Nowell ◽  
Murray M. Humphries
Keyword(s):  
Prey Species ◽  
Canis Latrans ◽  
Feeding Habits ◽  
Castor Canadensis ◽  
Generalist Predators ◽  
Generalist Predator ◽  
Wide Range ◽  
Game Reserve ◽  
Varied Diet ◽  
American Beaver

The feeding habits of generalist predators often vary among populations and regions. For example, Coyote (Canis latrans), which is a generalist predator distributed across North America, occupies a wide range of habitats and has a highly varied diet. In this observational study, we quantified the presence of mammalian prey items in 50 Eastern Coyote (Canis latrans var.) scats collected in late spring and summer in a private game reserve in southwestern Quebec. Nearly all scats contained hair of White-tailed Deer (Odocoileus virginianus; 44%), Moose (Alces americanus; 38%), or American Beaver (Castor canadensis; 38%). Although all three species are known to be consumed by coyotes, such a high proportion of Moose and White-tailed Deer simultaneously occurring in the diet of coyotes has not been previously reported. The uniqueness of the study area, with its relatively high abundance of all three prey species, may account for the uniqueness of the diet of Eastern Coyotes living there.

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