Dietary composition of cattle egrets (Bubulcus ibis) in the central Free State

2004 ◽  
Vol 23 (4) ◽  
pp. 90-98
Author(s):  
H. J.B. Butler

Analysis of 152 stomach samples of adult cattle egrets (Bubulcus ibis) collected over a period of five years in the central Free State showed this species to be mainly insectivorous. The Insecta, occuring in almost all stomach samples, are represented by prey items from 13 orders of which the Orthoptera, followed by the Coleoptera, Isoptera, Diptera and Lepidoptera, showed the highest frequency of occurrence. Amongst the non-insect invertebrates, the Araneae and Solifugae occured most frequently. Based on dry mass the Orthoptera and Isoptera constitute by far the most important components. Prey items of vertebrates combined represent only ca. 10% of the diet. Overall, the stomach contents of 75 chicks correspond with that of the adults, except that vertebrates make a significant contribution to the diet during the first week of the nesting phase. In general cattle egrets can be considered opportunistic feeders that concentrate on easily obtainable food sources which become sporadically available (partly because of their regular association with mammalian hosts).

2005 ◽  
Vol 24 (4) ◽  
pp. 118-123
Author(s):  
O. B. Kok ◽  
S.v.d. M. Louw ◽  
A. C. Kok

Analyses of 326 white-quilled korhaan (Eupodotis afraoides) stomach contents collected in the Free State and Northern Cape over a period of 20 years (1984-2004) showed this species to be a mixed feeder concentrating mainly on insects. Based on dry mass prey items of the Isoptera and Coleoptera form the bulk of the diet. According to frequency of occurrence coleopterans, more specifically members of the family Curculionidae, are utilised most often. Indications are that the curculionids, owing to their size and relative hardness of the exoskeleton, fulfil an accessory function with regard to the physical breakdown of coarse food items in the muscular stomach.


2007 ◽  
Vol 28 (4) ◽  
pp. 485-491 ◽  
Author(s):  
Diana Cupsa ◽  
Tibor Hartel ◽  
Severus-Daniel Covaciu-Marcov ◽  
István Sas ◽  
Éva-Hajnalka Kovács ◽  
...  

Abstract We examined the diet of Hyla arborea over its entire activity period (March to late September, 2004), and analysed a total of 585 adult samples. From the stomach contents we identified plant remains, shed-skin fragments, and animals. We identified a total of 2976 prey items, almost all of which originated from the terrestrial environment. Adult araneans and coleopterans were the most abundant prey items in the diet of the studied tree frogs. Some of the prey items become abundant in certain parts of the year (e.g. Homoptera, Lepidoptera larvae, Trichoptera). The dietary diversity index is high and exhibits seasonal changes. During the period of study an important seasonal change was observed in feeding intensity and in the type of consumed prey. Our results show that Hyla arborea has a broad dietary diversity which was expected as a consequence of exploiting the habitat both vertically and horizontally, possibly allowing access to a broader spectrum of prey.


2002 ◽  
Vol 21 (1) ◽  
pp. 16-18
Author(s):  
A. C. Kok ◽  
O. B. Kok

Stomach contents of 51 bird species that posed a potential threat to aviation were collected at the Bloemfontein airport over a period of 11 years (1985-1995). Numerically the crowned plover (Vanellus coronatus), and the lesser kestrel (Falco naumanni), blacksmith plover (V. armatus), whitewinged korhaan (Eupodotis afraoides), doublebanded courser (Smutsornis africanus), spotted dikkop (Burhinus capensis), cattle egret (Bubulcus ibis), Swainson’s francolin (Francolinus swainsonii) and Orange River francolin (F. levaillantoides) in sequence of importance, constituted 91,0% of the total sample (3 544). In general insects can be considered the main food source of the birds concerned. Based on dry mass composition the Isoptera, followed by the Coleoptera and Orthoptera, constituted the most important component in the diet. The Isoptera, more specifically the harvester termite (Hodotermes mossambicus), is, moreover, the only important prey taxon showing a conspicuous utilisation peak during the relative food shortage of the dry season. Evidently, temporary superabundant food sources that periodically come about in grassland habitats are opportunistically utilised by the birds.


2013 ◽  
Vol 13 (1) ◽  
pp. 376-379 ◽  
Author(s):  
Akemi Shibuya ◽  
Jansen Zuanon

In spite of the fact that catfish have rarely been reported as food items in the diets of freshwater stingrays, they are commonly observed in the stomach contents of species inhabiting the Solimões and Negro rivers in the Brazilian Amazon. The stomach contents of six rays from the Solimões River and 64 from the Negro River were analyzed, and catfishes (distributed among the families Callichthyidae, Cetopsidae, Doradidae and Loricariidae) were found in the stomach contents of four and 10 of these rays, respectively, comprising a frequency of occurrence of 20%. These data indicate a relevant participation of catfishes in the diets of potamotrygonid rays in the Amazon, and may reflect the regional diversity and abundance of Siluriformes in the region.


2020 ◽  
Vol 146 (2) ◽  
Author(s):  
Oldřich Kopecký

Urodeles, including European newts, are usually sexually dimorphic predators. Among newts, the alpine newt has the most pronounced sexual size dimorphism (in favour of females). Gender is a factor that is often associated with intra-specific diet differences. Despite the significant number of dietary studies on the alpine newt, some topics such as the breadth of the trophic niche and its overlap between sexes, or inter-sexual differences in qualitative and quantitative composition of prey remain unresolved. The present study dealing with these questions was conducted at two localities (ponds at an elevation of about 450 m) in the Czech Republic. Newts were captured from the banks during the entire breeding season using a dip net, and the stomach contents were extracted using a stomach flushing technique. Altogether 190 individuals were sampled, and a total of 1,417 prey items were obtained. The available food sources differed over the course of the breeding season, as newts changed the taxa they preyed on. This reflects the ability of newts to switch between several hunting strategies. The overall food niche overlap between the sexes was relatively large (C = 0.761, resp. C = 0.797). Inter-sexual differences were detected at both localities, mainly in the number of prey items consumed from the most important prey categories such as Rana eggs or Isopoda, which were consumed in higher numbers by females. The findings of this study suggest that females are more sensitive to the trade-off between energy intake and expenditure during the breeding season.


Author(s):  
A. Quetglas ◽  
F. Alemany ◽  
A. Carbonell ◽  
P. Merella ◽  
P. Sánchez

Stomach contents of Todarodes sagittatus caught by trawlers working from 100 to 800 m depth in the Balearic Sea (western Mediterranean) were studied. From the 348 stomachs examined (153 males and 195 females) 33.62% were empty (39.21% in males and 29.74% in females). The diet of the squid was composed of 58 different prey items belonging to four major groups: Osteichthya, Crustacea, Cephalopoda and Chondrichthya. Osteichthyes, crustaceans and cephalopods were the most common prey, with a frequency of occurrence value of 84.85, 48.92 and 29.87% respectively. A change in the diet as the squid grows was observed, since juveniles feed basically on fishes while adults prey more actively on crustaceans. Analysis of the diet by size-classes reflected an ontogenetic migration to deeper waters since, parallel to the increase of size, a raise in the percentage of prey species inhabiting deeper waters was detected. Cannibalism was quite frequent, since T. sagittatus was the second most common cephalopod prey. Females had higher fullness-weight index and lower emptiness index than males, which reflects their major energetic demand for egg production.


2012 ◽  
Vol 102 (2) ◽  
pp. 131-137 ◽  
Author(s):  
Marta J. Cremer ◽  
Pedro C. Pinheiro ◽  
Paulo C. Simões-Lopes

The present study provides information about the diet of sympatric populations of small cetaceans in the Babitonga Bay estuary. This is the first study on the diet of these species in direct sympatry. The stomach contents of seven Guiana dolphins Sotalia guianensis and eight franciscanas Pontoporia blainvillei were analyzed. The prey of both cetaceans was mostly teleost fishes, followed by cephalopods. We identified 13 teleost fishes as part of the diet of the franciscanas, and 20 as part of the diet of Guiana dolphins. Lolliguncula brevis was the only cephalopod recorded, and was the most important prey for both cetaceans. Stellifer rastrifer and Gobionellus oceanicus were also important for franciscana, so as Mugil curema and Micropogonias furnieri were important for Guiana dolphins. Stellifer rastrifer and Cetengraulis edentulus were the fishes with the highest frequency of occurrence for franciscana (50%), while Achirus lineatus, C. edentulus, S. brasiliensis, Cynoscion leiarchus, M. furnieri, M. curema, Diapterus rhombeus, Eugerres brasilianus and G. oceanicus showed 28.6% of frequency of occurrence for Guiana dolphins. Franciscanas captured greater cephalopods than the Guiana dolphins in both total length (z= -3.38; n= 40; p< 0.05) and biomass (z = -2.46; n = 40; p<0.05). All of the prey species identified occur inside the estuary, which represents a safe habitat against predators and food availability, reinforcing the importance of the Babitonga Bay for these cetacean populations.


2020 ◽  
Vol 32 ◽  
Author(s):  
Tatiane Araujo Santos ◽  
Thamires Souza Gonçalves ◽  
Patricia Silva do Nascimento ◽  
Cézar Augusto Freire Fernandes ◽  
Francisca Edna de Andrade Cunha

Abstract: Aim Identify seasonal variations in the diet of juvenile living in the estuary of the Parnaíba River Delta. Methods Food items were identified through analysis of stomach contents, and later submitted to analysis by regular methods for Frequency of Occurrence (FO), Frequency Numerical (FN), Gravimetric Frequency (FW) and Relative Importance Index (IRI). Results Juvenile diet of Elops saurus that inhabit the lagoons in the Parnaíba delta was composed in order decreasing of importance by Osteichthyes (Teleostei), Insecta and Crustacea in addition to Polychaeta and Nematoda. It was also observed a high frequency of occurrence of fragments of plastics in the diet. In the rainy season, 17 items were recorded in the diet, whereas in the dry season only 7 items were present. Relative Importance Index showed high presence of the Teleostei fish (69.93%) on diet of E. saurus during the rainy season, whereas during the dry period the insects of the families Corixidae (43.25%) and Dysticidae (39.16%). Conclusions With the study it was possible to identify that juvenile are piscivorous in the rainy season when there is a higher availability of prey in the environment and insectivores in the dry season when it reduces the supply of food, indicating feeding flexibility to environmental alterations.


2015 ◽  
Vol 72 (5) ◽  
pp. 1359-1369 ◽  
Author(s):  
Michael J. Miller ◽  
Jeff Dubosc ◽  
Elodie Vourey ◽  
Katsumi Tsukamoto ◽  
Valerie Allain

Abstract Leptocephali, the larvae of eels, grow to large sizes and are widely distributed in tropical and subtropical oceans. Their role in oceanic food webs is poorly known because they are rarely reported as food items in fish stomach content studies. Data from 13 years of research on the trophic dynamics of Pacific Ocean predatory fish indicate that among 8746 fish of 76 species/taxa (33 families) that had been feeding, only 16 fish of 6 species had remains of 34 leptocephali in their stomachs. Only 0.013% of the 256 308 total prey items were leptocephalus larvae, and 0.03% of the total prey items were juvenile or adult eels (mostly snipe eels: Nemichthyidae). There were 10 fish of 2 species of lancetfish (Alepisaurus spp., n = 152), 2 rainbow runners (Elagatis bipinnulata, n = 222), and 2 yellowfin tuna (Thunnus albacares, n = 3103) that had leptocephali in their stomach contents, but all except one T. albacares (contained 15 leptocephali) had each eaten ≤3 leptocephali. A swallower, Pseudoscopelus sp., and a frigate tuna, Auxis thazard, had eaten single leptocephali. Twenty-eight bigeye tuna, Thunnus obesus, had eaten 76 juvenile/adult nemichthyid or serrivomerid eels. A literature survey found that only 15 out of 75 examined publications listed leptocephali in the stomach contents of a total of 6 species out of ∼ 42 300 predatory fish of 40 species. The transparency of leptocephali and their apparent mimicry of gelatinous zooplankton could contribute to lower rates of predation. Their soft bodies likely digest rapidly, so although this study and existing literature indicate that leptocephali sometimes contribute to predatory fish diets, particularly for fish that do not exclude gelatinous prey types, and fish with low digestion rates in their stomachs such as lancetfish, their levels of contribution to fish diets and the impacts of predators on eel recruitment remain uncertain.


2024 ◽  
Vol 84 ◽  
Author(s):  
F. M. Dutra-Vieira ◽  
M. S. Silva ◽  
G. S. Vieira ◽  
A. S. Carvalho ◽  
B. C. Schimming

Abstract The present study aimed to evaluate the diet of the free-living crab-eating fox by identifying the stomach contents of the 17 crab-eating foxes (Cerdocyon thous) roadkilled in two conservation units, both located in the Amazon rainforest. The food items were quantified by frequency of occurrence (FO) and percentage of occurrence (PO). The stomach contents were analysed for dry matter (DM), crude protein (CP), crude fibre (CF), ether extract (EE), and mineral matter (MM). Nitrogen-free extractives (NFE), metabolisable energy (ME) values, as well as the energy need for maintenance were estimated. The composition of the diet for the crab-eating fox presented 29 food items from the different taxonomic groups, with a greater diversity of items of animal origin (n=22), although the highest frequency of occurrence was gramineae (Poaceae) (41.18%). Among the items of animal origin, 21% were mammals, 18% reptiles, 10% amphibians, 9% invertebrates and 3% birds. A high content of CF (62.76%) were determined. Nitrogen-free extractive and dry matter averages were 5.91% and 141.82 kcal/100g, respectively. The average maintenance energy was 447.01 kcal/day. These findings suggesting that the crab-eating foxes have a generalist diet with an omnivorous diet in the Amazon basin, feeding on gramineae, fruits, insects, snakes, amphibians, birds and small mammals and have the same feeding habit that present in other Brazilian biomes.


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