Feeding Biology Research Articles

Food and Feeding Biology of Nile Tilapia (Oreochromis niloticus) in Lake Langeno, Ethiopia

This study aimed to investigate the natural feeding behavior of Nile tilapia in Lake Langeno, Ethiopia, with emphasis on potential spatial, size and seasonal effects on ingested food items. This study of the food and feeding biology of O. niloticus in Lake Langeno, Ethiopia, was conducted from March 2016to February 2017. Fish samples were collected monthly from six different sampling sites using different mesh sizes of gillnets. A total of 610 fish specimens with full stomachs were considered for the assessment of feeding biology. In total, seven food items, namely phytoplankton, zooplankton, insects, detritus, macrophytes, fish parts and nematodes, were identified from the fish stomach contents. Phytoplankton was the most commonly consumed food prey, followed by detritus, zooplankton and macrophytes. The other food items were occasionally and randomly consumed. Phytoplankton and detritus were the dominant food prey in the dry season, with zooplankton and macrophytes the main prey during the wet months. The contribution of phytoplankton, zooplankton and insects were slightly highest in small-sized groups (<10 cm), whereas detritus, macrophytes and fish parts were highest in larger-size groups (>20 cm) (p < 0.05). The present results point to a concurrence of the relative importance of dietary items at the individual level, species level and among the study sites. Phytoplankton was the primary consumed food item, which indicates the specialist feeding strategy of Nile tilapia in the lake. Generally, food items of plant origin, typically associated with less protein content than animal origin food items, dominated the stomach contents of Nile tilapia. The dietary pattern of Nile tilapia in Lake Langeno shifts with size and season, aspects that might warrant further study in view of aquaculture applications as well as climate change.

Skull morphology of four Antarctic fulmarine petrels (Aves: Procellariiformes): insights into their feeding biology

Skull morphology of four Antarctic fulmarine petrels (Aves: Procellariiformes): insights into their feeding biology

The Effects of Host Availability and Fitness on Aedes albopictus Blood Feeding Patterns in New York.

Aedes albopictus is a competent vector of numerous pathogens, representing a range of transmission cycles involving unique hosts. Despite the important status of this vector, variation in its feeding patterns is poorly understood. We examined the feeding patterns of Ae. albopictus utilizing resting collections in Long Island, NY, and contextualized blood meal sources with host availability measured by household interviews and camera traps. We identified 90 blood meals, including 29 humans, 22 cats, 16 horses, 12 opossums, 5 dogs, 2 goats, and 1 each of rabbit, rat, squirrel, and raccoon. This is only the third study of Ae. albopictus blood feeding biology that quantitatively assessed domestic host availability and is the first to do so with wild animals. Host feeding indices showed that cats and dogs were fed upon disproportionately often compared with humans. Forage ratios suggested a tendency to feed on cats and opossums and to avoid raccoons, squirrels, and birds. This feeding pattern was different from another published study from Baltimore, where Ae. albopictus fed more often on rats than humans. To understand whether these differences were because of host availability or mosquito population variation, we compared the fitness of New York and Baltimore Ae. albopictus after feeding on rat and human blood. In addition, we examined fitness within the New York population after feeding on human, rat, cat, horse, and opossum blood. Together, our results do not indicate major mosquito fitness differences by blood hosts, suggesting that fitness benefits do not drive Northeastern Ae. albopictus feeding patterns.

Первый случай гнездования малого волчка Ixobrychus minutus и гибридов I. minutus с I. sinensis на Дальнем Востоке России

In 2007 in the suburbs of Vladivostok we discovered the first nesting settlement of the Chinese bittern Ixobrychus sinensis in the Russian Far East and documented the first reliable case of breeding of the little bittern I. minutus at a distance of about 3,000 km from the boundaries of its main range. In the subsequent years, 2008–2010, one pair of bitterns nested every year in the study area. The colour of the body and the shape of the beak of both partners were largely typical of the little bittern, but there were signs characteristic of the Chinese bittern, which made it possible to identify them as hybrid individuals. For the first time evidence of hybridisation was obtained for species of the genus Ixobrychus. Six nests, 37 eggs and 26 chicks of Chinese bitterns and hybrids were described. Based on the collection material (95 carcasses) and the data of hidden video filming (112 hours), the species and species-specific morphometric parameters of bitterns were determined. In a comparative perspective the morphology and colouration, nesting biology, behaviour of adults and juveniles, and the daily rhythm of heating and feeding nestlings were described in detail. Despite the allopatric distribution (with joint wintering grounds in India) and a clear morphological gap, habitats, phenology and biology of reproduction, behaviour and feeding as well as most types of calls of these species appeared to be largely similar. In the case of dispersal of the little bittern to the east, the above factors can contribute to hybridisation.

Parâmetros biológicos da lagarta-do-fumo (Lepidoptera: Noctuidae) alimentada com espigas de milho em diferentes temperaturas

ABSTRACT The tobacco budworm Chloridea (Heliothis) virescens (F.) (Lepidoptera: Noctuidae) has been recently reported in corn crops. However, there is no information regarding the biology of this species feeding on corn cobs. Additionally, the relationship between temperature and tobacco budworm feeding habits is important to project the adaptation of the insect in corn crops at different times and regions. This study aimed to investigate the development of C. virescens feeding on corn cobs, under controlled laboratory conditions, at three temperatures (25 ± 1 ºC, 28 ± 1 ºC and 31 ± 1 ºC). Although adult budworms were observed at all temperatures, the larval development period was reduced at 31 ± 1 ºC, resulting in a lower grain consumption. On the other hand, biological parameters such as larval and pupal viability, pupal weight and sex ratio did not vary with temperature. During the adult stage, a similar fecundity was recorded at all temperatures; however, the egg viability was zero. The optimal temperature for the C. virescens development was between 25 ± 1 ºC and 28 ± 1 ºC. The temperature of 31 ± 1 ºC affects the eggs development, preventing the next generation of tobacco budworms.

Population, Distribution, Sub-species, Feeding and Breeding Biology of Black Kite: A Review

The black kite is a medium-sized raptor and widely distributed on all continents except Nearctic and Neo-tropic zone. It plays a crucial role in the ecosystem and maintains prey populations, especially for rodents. They preferred a wide variety of habitats, including open areas, grasslands, scattered vegetation, agricultural land and also adapted towards cities and towns. Black kite diets are extremely diverse; they typically consume grasshoppers, birds, rodents, bats and dead animal carcasses. A diet of black kite varies geographically and depends on the availability and abundance of prey population. The breeding season for black kites begins in March and lasts until April and also vary and depending on the subspecies. Black kites usually construct nest upon large trees, mobile tower and electric pylons. They generally utilise plant matter as nesting material, but sometime they also utilise clothes, paper and plastic. Population of black kite is declining due to poisoning by pesticides, lack of roosting and nesting sites, lack of prey availability and electrocutions. Environmental conditions such as extreme temperature, wind velocity and rainfall influence the daily activity and breeding biology of black kites. Habitat fragmentation, anthropogenic interference, deforestation, pesticide pollution and electrocutions cause negative impacts on raptor survival, including the black kite.

Observation of a coral-dwelling gall crab (Cryptochiridae) in a dead coral host highlights their vulnerability to reef degradation

Coral-associated fauna contributes greatly to coral reef biodiversity. Many species are obligately associated with their hosts on which they depend for food and/or refuge from predators. Their close relationship with their hosts makes them vulnerable to coral mortality. Here I report a coral-dwelling gall crab (Cryptochiridae) inhabiting a partially dead Echinopora Lamarck, 1816 coral, at Magoodhoo Island, Faafu Atoll, Maldives. Cryptochirids are thought to feed off the mucus provided by their coral host, although some questions about their feeding biology remain. This observation highlights that these crabs remain associated with a dead host, even if it can no longer provide nutrients. The strong host association makes gall crabs vulnerable to widespread habitat degradation.

Relationships between length-weight, length-length, and fish length to otolith morphometry in Rita rita (Hamilton, 1822)

The present study deals with fish length-weight, length-length, length-otolith size and length-otolith weight relationships in Rita rita. Specimens (N = 117) were collected monthly from September 2018 to August 2019 from Narora site of the River Ganga, India. The slope (b) in length-weight relationship equation was 2.40, suggesting a negative allometric growth pattern. The Student’s t-test showed no significant differences in the size of right and left otoliths in Rita rita, therefore, a single linear regression based on left otoliths was used. Fish length was plotted against otolith length, otolith height and otolith weight. The linear regression model was found to fit the data well for fish length to otolith size. Fish length was positively correlated with otolith height (R2 = 0.97), otolith length (R2 = 0.94) and otolith weight (R2 = 0.91). The mean value of condition factor was 1.13, which suggested a good condition of the target fish species in the River Ganga. Findings of this study could be used to study the population characteristics of Rita rita, and to explore the food and feeding biology of piscivores based on correlating the otolith morphometry of the prey items to the fish length at age.

Experimental Infection of Ticks: An Essential Tool for the Analysis of Babesia Species Biology and Transmission.

Babesiosis is one of the most important tick-borne diseases in veterinary health, impacting mainly cattle, equidae, and canidae, and limiting the development of livestock industries worldwide. In humans, babesiosis is considered to be an emerging disease mostly due to Babesia divergens in Europe and Babesia microti in America. Despite this importance, our knowledge of Babesia sp. transmission by ticks is incomplete. The complexity of vectorial systems involving the vector, vertebrate host, and pathogen, as well as the complex feeding biology of ticks, may be part of the reason for the existing gaps in our knowledge. Indeed, this complexity renders the implementation of experimental systems that are as close as possible to natural conditions and allowing the study of tick-host-parasite interactions, quite difficult. However, it is unlikely that the development of more effective and sustainable control measures against babesiosis will emerge unless significant progress can be made in understanding this tripartite relationship. The various methods used to date to achieve tick transmission of Babesia spp. of medical and veterinary importance under experimental conditions are reviewed and discussed here.

The role of cholecystokinin and peptide YY in feed intake in Atlantic halibut (Hippoglossus hippoglossus) larvae

Control of appetite and feed intake in fish larvae are still largely unexplored. Two of the key players in controlling vertebrate's feed intake are cholecystokinin (CCK) and peptide YY (PYY). Here we investigated the mRNA expression of pyy, cck and cck receptors (cckr) in the brain (head) and gut of Atlantic halibut larvae in response to three consecutive meals. We used Artemia nauplii cysts that are commonly ingested by halibut larvae when present as inert feed, and three water-soluble extracts as attractants to stimulate appetite. Cyst intake was not affected by the use of attractants and overall ingestion rate was low. Differences in mRNA expression of cck and pyy were observed between the halibut larvae that had eaten and those that had not despite readily available feed (cysts), supporting that mechanisms for control of feed intake are at least partly functional. All genes analysed were present in the brain and gut, however the different expression profiles between paralogues suggest potential divergent functions. In the gut, cck2 and pyyb mRNA expression was significantly higher in the larvae that ate cysts compared to larvae that decided to not eat, indicating that these genes play a satiety function in the halibut larvae similar to the general vertebrate scheme. However, cck2, cck2r1, and pyy mRNA expression in the brain were lower in the fed-filled larvae group compared to larvae before eating, which contrasts with the presumable anorectic function of these genes. Further research is required to fully evaluate how PYY and CCK affect the feeding biology in halibut larvae, contributing to formulate inert diets that can stimulate appetite and feed intake.

Perception of Dissolved Food-Related Compounds by the Sea Urchin Paracentrotus lividus (Echinodermata: Echinoidea)

Echinoid feeding biology is well known but their sluggish responses to chemical stimuli have turned them into inadequately worked in the field of chemoreception. Echinoid responses to chemical stimulation had allowed, so far, only qualitative analyses based on tube-feet activity, directional, or masticatory movements, and artificial agarose foods. Besides stimulation through plumes of dissolved organic compounds and response analysis based on tube-feet activity, we propose another method to chemically stimulate echinoids that allows for fast and unambiguous responses and thus, quantitative analyses. Small squared pieces of absorbent semi-synthetic cleaning cloths, soaked with specific chemical compounds (simulacra), such as water insoluble lipid oils, were deposited singly or concurrently with a blank on the aboral hemisphere of each sea urchin, allowing choice and eventual transport down to the mouth by tube feet and spines of one or both cloths. The responsiveness ofParacentrotus lividuswas clearly dependent on its nutritional state. Well-fed sea urchins (maize whole grains) rarely responded, while the ones fed with less caloric rations (Kombu seaweed) responded faster and objectively. Stimulating sea urchinP. lividuswith 41 different food-related compounds, such as carbohydrates, proteins, peptides and amino acids, oils and fatty acids, and purified chemicals related with some human basic tastes, it was possible to evidence a clear ability of this echinoid species to positively discriminate proteins, starches, and a very few oils. Perceived as incitants/stimulants we have only found among proteins gliadin (from wheat gluten) but not casein (from bovine milk), among polysaccharides starch but not laminarin (from kelp) or glycogen (from mussels), and among lipids only the fatty acid linolenic acid. Among tissues, Kombu alga flesh and mussel flesh were readily perceived as both incitant/stimulant but not Kombu and mussel extracts. Therefore, the combined results reported here provide evidence forP. lividusas an omnivorous species rather than a strictly herbivorous marine species. However, the restricted group of food-related compounds perceived by this species as incitants or suppressants and as stimulants or deterrents was shown to be remarkably related to other vertebrates whose kinship was confirmed by the sequencing of the genome of another plant-eater sea urchin.

Population structure, habitat preferences, feeding strategies, and diet of the brittle star Ophiopholis aculeata in nearshore and offshore habitats of the northwest Atlantic

AbstractOphiopholis aculeata is a ubiquitous brittle star (Echinodermata: Ophiuroidea) known to occur from the upper subtidal to the bathyal zone. Individuals from shallow inshore habitats (rhodolith beds and rock fields) and deeper offshore locations in eastern Canada were studied to assess the population structure, habitat selection, diet, and feeding strategies of this species through use of stable isotope analyses, gut contents, and laboratory experiments. Potential drivers of habitat selection such as depth, light conditions, body size, sex, intraspecific competition, and presence of predators were examined. This study highlighted variable population size structures and abundances as well as diversified food sources and feeding strategies (i.e., suspension and deposit feeding, scavenging, predation on live organisms, and even cannibalism) as a function of native depth and habitat. It also revealed that studies on the feeding biology of brittle stars must carefully consider sex and life stage as driving factors.

Food and Feeding Habits of Wedge Clam (Donax cuneatus) Off Thoothukudi, Gulf of Mannar, India

Background: Bivalves are benthic animals existing in coastal habitats, particularly mudflats and tidal. Because of their availability, rich protein content and cheaper cost, they contribute a major portion of the small-scale fishery resource worldwide. Limited information has been available on the food-feeding and habitat structures of bivalves along Indian waters. Therefore, the present investigation was carried out to know the food-feeding and habitat preferred by wedge clam, Donax cuneatus off Thoothukudi, Gulf of Mannar, India. Methods: Soil, water and wedge clam samples were collected from the selected site from September 2019 to March 2021 and soil texture, water quality parameters and gut contents were analyzed at the laboratory. Result: During the study period, salinity, water temperature, pH and dissolved oxygen (DO) were in the range from 31-37‰, 24-28°C, 7.7-8.7 and 4.1-5.8 mg/l, respectively. Wedge clams were mainly observed at sandy beaches up to 10 cm in depth. Donax cuneatus mainly feeds on detritus (65%), followed by phytoplankton (31%) and zooplankton (4%). Hence, the diverse fluctuation of food particles, season-specific food and feeding biology and local environmental conditions at the studied region might be the responsible features for the availability of Donax cuneatus.

Reproductive and feeding biology of unicorn leatherjacket, Aluterus monoceros from the Bay of Bengal, Northern Indian Ocean

AbstractNo prior comprehensive information on the reproductive biology and trophodynamics of Aluterus monoceros was globally available. The present study was performed on 1036 individuals landed along the western Bay of Bengal during 2017 to 2019. Length ranged between 25.3–64.4 cm in females (mean at 48.34 cm) and from 21.5–64.1 cm in males (mean at 47.83 cm). Growth was negatively allometric with no significant difference between sexes. Sex ratio (F:M) was 1.03 with variations based on sizes and months. Size at sexual maturity for females and males was 40.85 and 41.60 cm, respectively. The species spawned throughout the year with major and minor peaks during February to May and October and November. Absolute fecundity increased linearly with length and weight and ranged from 33,640 eggs to 12,39,202 eggs. Stomachs were empty or with trace amounts of food in 59.17%, part-full in 34.07% and full in 6.76% of the fishes. Stomach vacuity and fullness and predator–prey weight ratios varied with an increase in body size, implying higher feeding intensity in large-sized fishes. Feeding activity was more intense during June–August and less during the peak spawning months. The species is omnivorous and a bottom feeder. Teleosts contributed the most to the prey items (43.23% by Index of Preponderance) implying preference for carnivory. Ontogenetic shifts and seasonal variations in prey items were observed. The present study provides paramount information that can significantly contribute to the management and conservation of monacanthid stocks in northern Indian Ocean.

Diel pattern in common carp landings from angling competitions corresponds to their assumed foraging activity

Increased foraging activity increases vulnerability of fish to angling. Foraging activity of free-ranging common-carp (Cyprinus carpio L.) is assumed to be mostly nocturnal. Thus, it is assumed that the number of carp caught in angling competitions will be higher during the night than during the day. Also, common carp are able to learn the position of new feeding spots that they exploit repeatedly. This ability may lead to an increase in number of landed carp each consecutive day of angling competitions as new carp learn the position of newly established feeding-spots. These hypotheses were tested using data from 14 carp-oriented angling competitions conducted in four European countries. As expected, carp landings were most frequent at night and the number of carp landed increased non-monotonously throughout the competitions. These findings may be important for essential feeding biology of wild common carp with valuable implications for anglers and management of non-native carp.

Gastropod first intermediate hosts for two species of Monorchiidae Odhner, 1911 (Trematoda): I can’t believe it’s not bivalves!

The trematode superfamily Monorchioidea comprises three families of teleost parasites: the Monorchiidae Odhner, 1911, Lissorchiidae Magath, 1917, and Deropristidae Cable & Hunninen, 1942. All presently known lissorchiid and deropristid life cycles have gastropods as first intermediate hosts, whereas those of monorchiids involve bivalves. Here, we report an unexpected intermediate host for monorchiids; two species of Hurleytrematoides Yamaguti, 1954 use gastropods as first intermediate hosts. Sporocysts and cercariae were found infecting two species of the family Vermetidae, highly specialised sessile gastropods that form calcareous tubes, from two locations off the coast of Queensland, Australia. These intramolluscan infections broadly corresponded morphologically to those of known monorchiids in that the cercariae have a spinous tegument, oral and ventral suckers, a simple tail and distinct eye-spots. Given the simplified morphology of intramolluscan infections, genetic data provided a definitive identification. ITS2 rDNA and cox1 mtDNA sequence data from the gastropod infections were identical to two species of Hurleytrematoides, parasites of butterflyfishes (Chaetodontidae); Hurleytrematoides loi McNamara & Cribb, 2011 from Moreton Bay (south-eastern Queensland) and Heron Island (southern Great Barrier Reef) and Hurleytrematoides morandi McNamara & Cribb, 2011 from Heron Island. Notably, species of Hurleytrematoides are positioned relatively basal in the phylogeny of the Monorchiidae and are a sister lineage to that of species known to infect bivalves. Thus, the most parsimonious evolutionary hypothesis to explain infection of gastropods by these monorchiids is that basal monorchiids (in our analyses, species of Cableia Sogandares-Bernal, 1959, Helicometroides Yamaguti, 1934 and Hurleytrematoides) will all prove to infect gastropods, suggesting a single host switching event into bivalves for more derived monorchiids (17 other genera in our phylogenetic analyses). A less parsimonious hypothesis is that the infection of vermetids will prove to be restricted to species of Hurleytrematoides, as an isolated secondary recolonisation of gastropods from a bivalve-infecting lineage. Regardless of how their use arose, vermetids represent a dramatic host jump relative to the rest of the Monorchiidae, one potentially enabled by their specialised feeding biology.

The burden of size and growth for the juveniles of large mammalian herbivores: Structural and functional constraints in the feeding biology of juveniles relative to adults in red kangaroos, Osphranter rufus.

Juvenile mammals in their postweaning developmental stages face many challenges in transitioning to adulthood. Among large grazing species such as ruminant bovids and cervids, an overarching challenge is acquiring and processing sufficient nutrients to survive and grow, with a gut that may not yet be fully developed. Marsupial kangaroos of Australia face similar challenges; they also digest vegetation by fermentation in a large foregut. In red kangaroos, Osphranter rufus (=Macropus rufus), the dominant species of Australia's arid interior, females may breed continuously; however, juvenile recruitment to the adult population is irregular and coincident with sporadic rainfall.As compared with adult females, the nutritional requirements of juvenile O. rufus are high in relation to their body mass (BM), largely due to the cost of their rapid growth. We examined processes that juveniles have in their morphology, physiology, and behaviors to meet their elevated nutritional needs, by comparing recently weaned juveniles of both sexes and adult female O. rufus in their desert habitat. Features studied include relative body sizes, relative dimensions, and capacities of principal gut regions, the foregut, small intestine, caecum, and large intestine with rectum. Also examined were digesta attributes and rates of digesta excretion. Additionally, the rates of change in skull parameters and dental characteristics to maturity were assessed. Field determinations of diet choice were made for both age classes.In juveniles, the content masses of major gut structures were related to body mass (BM), as were those of adult females, that is, ~BM1.0. In both age classes, the digesta mass of the foreguts exceeded 75% of the total digesta mass. Diets of both juvenile and adult O. rufus largely focused on grasses. Juveniles had higher rates of digesta excretion while foraging than adults. In addition, the foregut contents in juveniles occupy proportionally less of the total gut than in adult females. Together, the higher excretion rate and smaller relative foregut of juveniles suggest that they necessarily focus on forage that can be rapidly digested, such as young, green grasses, or herbage.Comparison of the skulls of juveniles and adults revealed how this harvest can occur. Relative to BM, juveniles had skulls of larger volume than adults. Additionally, during growth the skull lengthens proportionally faster than increasing BM. By weaning, the dimensions of the incisor bite of juveniles neared those of adult females. The area of wear on premolars/molars increased only slowly relative to the development of incisors, further pointing to juveniles selecting more digestible forage than adults. The intermittent availability of such forage, principally young grasses, appears key to the significant recruitment into the O. rufus population in their arid habitat.

Contrasting metabolic strategies of two co-occurring deep-sea octocorals

The feeding biology of deep-sea octocorals remains poorly understood, as attention is more often directed to reef building corals. The present study focused on two common deep-water octocoral species in the Azores Archipelago, Dentomuricea aff. meteor and Viminella flagellum, aiming at determining their ability to exploit different food sources. We adopted an experimental approach, with three different food sources, including live phytoplankton, live zooplankton and dissolved organic matter (DOM), that were artificially enriched with 13C and 15N (C and N tracers). The presence of tracers was subsequently followed in the coral tissue, C respiration and particulate organic C and N (POC and PON) release. In both species, feeding with zooplankton resulted in significantly higher incorporation of tracers in all measured variables, compared to the other food sources, highlighting the importance of zooplankton for major physiological processes. Our results revealed contrasting metabolic strategies between the two species, with D. aff. meteor acquiring higher amounts of prey and allocating higher percentage to respiration and release of POC and PON than V. flagellum. Such metabolic differences can shape species fitness and distributions and have further ecological implications on the ecosystem function of communities formed by different octocoral species.

Viviparous sea snakes can be used as bioindicators for diverse marine environments

Shallow tropical marine ecosystems are under great anthropogenic pressure due to habitat destruction, overfishing, shrimping, climate change, and tourism. This is an issue of global concern as such environments hold a tremendous biodiversity much of which remains to be described. The present situation urgently calls for time- and resource-efficient methods to identify and delineate the most valuable remaining areas and to set up priorities for their management and conservation. Using indicator species can be a way to accomplish this goal. In this paper we evaluate whether viviparous sea snakes can serve as bioindicators for other rare or cryptic tropical marine fauna. Based on seven generally acknowledged criteria for bioindicators, we argue that using viviparous sea snakes as bioindicators can help monitoring marine habitats to gauge the effects of climate change, habitat change and loss, decline in biodiversity and other anthropogenic changes. However, to maximize their efficacy as bioindicators, deeper knowledge about viviparous sea snakes natural history is urgently needed. Topics for expanded research programs include the taxonomy of some groups, their breeding and feeding biology, habitat selection and their geographical distribution. Despite these gaps in our understanding, we argue that viviparous sea snakes can be utilized as bioindicators of marine ecosystem health. KEYWORDS: anthropogenic changes, conservation, herpetology, marine habitat, monitoring

Cranial Musculoskeletal Description of Black-Throated Finch (Aves: Passeriformes: Estrildidae) with DiceCT.

Synopsis Dietary requirements and acquisition strategies change throughout ontogeny across various clades of tetrapods, including birds. For example, birds hatch with combinations of various behavioral, physiological, and morphological factors that place them on an altricial–precocial spectrum. Passeriformes (=songbirds) in particular, a family constituting approximately more than half of known bird species, displays the most drastic difference between hatchling and adults in each of these aspects of their feeding biology. How the shift in dietary resource acquisition is managed during ontogeny alongside its relationship to the morphology of the feeding apparatus has been largely understudied within birds. Such efforts have been hampered partly due to the small size of many birds and the diminutive jaw musculature they employ. In this study, we used standard and diffusible iodine-based contrast-enhanced computed tomography in conjunction with digital dissection to quantify and describe the cranial musculature of the Black-throated Finch (Poephila cincta) at fledgling and adult stages. Our results reveal that in both the fledgling and the adult, cranial musculature shows clear and complex partitioning in the Musculus adductor mandibulae externus that is consistent with other families within Passeriformes. We quantified jaw-muscle sizes and found that the adult showed a decrease in muscle mass in comparison to the fledgling individual. We propose that this could be the result of low sample size or a physiological effect of parental care in Passeriformes. Our study shows that high-resolution visualization techniques are informative at revealing morphological discrepancies for studies that involve small specimens such as Passeriformes especially with careful specimen selection criteria.