Predation and prey-caching of Eastern Water Skinks Eulamprus quoyii by nesting Nankeen Kestrels Falco cenchroides in eastern New South Wales

The breeding diet of a pair of Nankeen Kestrels Falco cenchroides nesting in Beresfield, eastern New South Wales, in 2020 was investigated. By individual prey species, the diet comprised 61.3% reptiles (including two prey species not previously recorded in the Nankeen Kestrel diet—Eastern Water Skink Eulamprus quoyii and most likely Southern Rainbow Skink Carlia tetradactyla), 9.7% birds (including a new prey species—Superb Fairy-wren Malurus cyaneus), 6.4% invertebrates (two crickets: Grylloidea), 3.2% mammals (one House Mouse Mus musculus) and 19.4% unidentified prey items (percentages by number). During 31.5 h of observations, the male delivered 22/31 prey items (71%) and the female delivered 9/31 prey items (29%) to the nest tree. The average delivery rate over the entire nestling period was one prey item per hour. Prey-caching, whereby the female stored lizards in the fork of a tree and later retrieved them and fed them tothe single nestling, was observed. Further studies are needed to obtain well-documented accounts of prey-caching by Australian falcons.

Analysis of regurgitated pellets of Spotted Owlet Athene brama (Temminck, 1821) (Aves: Strigiformes: Strigidae) from Punjab, India

The present study was conducted to determine the diet of Spotted Owlet Athene brama. Analysis of 200 regurgitated pellets collected from eight different locations in Punjab (India) determined average weight, length, breadth and thickness to be 1.0g, 27.0mm, 16.0mm and 12.0mm, respectively. Remains of a total 433 individual prey were found in these pellets. Diet of Spotted Owlet consisted of both vertebrates (45.7%) and invertebrates (54.3%). Among vertebrates, mice (45.0%) were predominant, followed by frogs (0.5%) and birds (0.2%). Among invertebrates, diet mainly consisted of insects (53.8%) followed by molluscs (0.5%). Insects preyed upon by Spotted Owlet were predominantly of orders Coleoptera (34.9%), followed by Orthoptera (10.2%), Dermaptera (7.9%) and some unidentified orders (0.9%). The remnants of insects and molluscs in the pellets comprised of wings, legs, head, shells etc. The average number of mice consumed per pellet was 1.32, with a maximum capacity of consuming up to five mice per night.

Diet

Four methods were used to document the diet of cheetahs: incidental observations, radio tracking, tracking, spoor, and continuous follows. A combination of continuous follows and tracking spoor gave the best results. Steenbok were the most frequently killed species, but they did not dominate the diet in the same way as Thomson’s gazelle do in the Serengeti. Coalition males have a different diet profile from single males, single females, females with cubs, and sibling groups. For all but single males, the relative occurrence of prey species in the diet reflected its dietary importance in terms of kilograms of meat obtained. Gemsbok calves and adult ostrich were important prey for coalition males and springhares were important for single males. Three individual prey specializations for females were found; namely springbok specialists, steenbok/duiker specialists, and intermediates. Contrary to an earlier study, springbok were not found to be the most important prey species.

Consistent long-term behavioural traits are linked to morphological defences in common carp (Cyprinus carpio)

Individual prey often exhibit consistent behavioural differences in responses to risk. Here, we assess whether such behavioural consistency is linked to morphological changes that are known to result in differences in vulnerability to predators. Some fishes increase their depth-to-length ratio when under increased risk of predation, thereby reducing their risk to gape-limited predators. However, the development of these defences is limited by available resources. We asked whether behavioural tendencies associated with shelter seeking and activity are linked to differences in growth patterns. Common carp classified as ‘active/non-sheltering’ or ‘passive/sheltering’ based on their movement patterns and shelter use, showed consistency in behaviour over a 10-month period with active/non-sheltering fish developing a greater depth to length ratio than passive/sheltering fish. The effectiveness of anti-predator strategies in animals is an integrative function of both behaviour and morphology. Our works highlights a fascinating link between behavioural consistency and the development of adaptive morphologies.

On the food of the Eurasian pygmy owl (Glaucidium passerinum) in Slovakia

Data on the food of the Eurasian pygmy owl in Slovakia was collected in 1999−2014 at 12 breeding locations in 7 mountain ranges of the Western Carpathian Mts and 1 range belonging to the Eastern Carpathian Mts. The basis of the evaluation of the food spectrum of prey of G. passerinum was the collection of pellets, osteological remnants and feathers from birds beneath nest cavities and roosting places of females in the months of May to July, that is, in the period of feeding young in the nest. Overall samples of food from 12 nests at elevations of 650−1,260 m a.s.l. were collected; from the largest of the three nests in the upper Nitra Region, from one nest in the Západné Tatry Mts and from three nests in the Volovské vrchy Mts. We compared these data with existing published data from Slovakia. A higher share of birds (65.0%) was found in the obtained material than mammals (34.8%). In the samples from 12 locations 10 species of mammals and 33 species of birds were found among the 377 individual prey samples. Among mammals, forest species of rodents predominated: Clethrionomys glareolus (22.8%) and Apodemus flavicollis (6.6%). The species Microtus arvalis (2.7%) was less abundant than in the stores of food from the Chocské vrchy Mts (35.4%). From the broad spectrum of songbirds, no species exceeded a presence of 7%. Species from the families Sylviidae, Turdidae, Paridae and Fringillidae were more numerous, while the species Phoenicurus phoenicurus, Motacilla alba, Carduelis cannabina, Dendrocopos minor and Passer domesticus were among the more uncommon prey. In total 582 individual prey were determined from the food remnants of G. passerinum in Slovakia (present study and other published studies). The species Clethrionomys glareolus occurred with a higher dominance than average in the pellets of G. passerinum in the mountains which border the region of the upper Nitra. In the Belianské Tatry Mts the most abundant rodent species was Terricola subterraneus, while in the mountains of eastern Slovakia the yellow-necked mouse Apodemus flavicollis was most often hunted, and of the songbirds, the coal tit Periparus ater. Among songbirds hunted near the breeding grounds of G. passerinum in the Považský Inovec Mts the collared flycatcher Ficedula albicollis was the most numerous. Among the most numerous songbirds which are evenly represented in all compared areas were: Regulus sp., Certhia familiaris, Poecile montanus and Cyanistes caeruleus.

How sailfish use their bills to capture schooling prey

The istiophorid family of billfishes is characterized by an extended rostrum or ‘bill’. While various functions (e.g. foraging and hydrodynamic benefits) have been proposed for this structure, until now no study has directly investigated the mechanisms by which billfishes use their rostrum to feed on prey. Here, we present the first unequivocal evidence of how the bill is used by Atlantic sailfish ( Istiophorus albicans ) to attack schooling sardines in the open ocean. Using high-speed video-analysis, we show that (i) sailfish manage to insert their bill into sardine schools without eliciting an evasive response and (ii) subsequently use their bill to either tap on individual prey targets or to slash through the school with powerful lateral motions characterized by one of the highest accelerations ever recorded in an aquatic vertebrate. Our results demonstrate that the combination of stealth and rapid motion make the sailfish bill an extremely effective feeding adaptation for capturing schooling prey.