Mechanism of pellet egestion in great-horned owls (Bubo virginianus)

Duke, G. E.; Evanson, Oral A.; Redig, Patrick T.; Rhoades, D. D.

doi:10.1152/ajplegacy.1976.231.6.1824

Cited by 28 publications

(15 citation statements)

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“…The value is similar to that of spontaneous spike bursts (2.5 to 4.5 cpm) recorded from the thick gizzard muscle of roosters with implanted electrodes in the fed state (Clench and Mathias, 1996). These workers reported that each spike burst was associated with a slow wave complex, although previous workers had failed to demonstrate spontaneous slow wave activity in the gizzard of the chicken (Roche, 1974) or other avian species (Duke et al, , 1975(Duke et al, , 1976. The frequency is also close to that reported in fistulated ambulant turkeys (3.3 cpm) with implanted cannulas or electrodes and with implanted strain gauges (3.1 cpm) (Chaplin et al, 1992), but higher than that of spike bursts (0.7 to 1.9 cpm) recorded in chickens with implanted gizzard electrodes (Roche and Ruckebusch, 1978).…”

Section: Physiological Findingssupporting

confidence: 76%

Spatiotemporal mapping of the muscular activity of the gizzard of the chicken (Gallus domesticus)

et al. 2013

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We report the results of spatiotemporal mapping of the spontaneous actions of component muscles of the gizzard and associated structures in ex vivo preparations with combined superfusion and vascular perfusion. Ongoing spontaneous contraction of cranial and caudal thin muscles occurred at a frequency of 2.2 ± 0.1 cycles per minute. Contractions of M. tenuis craniodorsalis with mean duration of 2.8 ± 0.2 s commenced ventrally adjacent to the distal limit of the proventriculus and progressed dorsally at 2.02 ± 0.03 mm•s(-1) in a concerted front. Near simultaneous contraction of M. tenuis caudoventralis of mean duration of contraction of 4.7 ± 0.7 s commenced dorsally and progressed ventrally at a similar rate (2.1 ± 0.1 mm•s(-1)) and in a similar manner. Contraction of the caudoventralis preceded that of craniodorsalis (mean 1.1 ± 0.15 s). Contraction of the 2 tenuis muscles was synchronous with the first component peak of the cyclic increase in lumen pressure and with distension of the crassus musculature. Contraction of the M. crassus caudodorsalis muscle coincided with the second component peak and was followed by distension of the tenuis musculature. The latter commenced before the relaxation of the tenuis muscles. Contractions of the crassus muscle propagated rapidly at right angles to the orientation of the muscle fibers at a faster velocity than that of the tenuis musculature. The durations of the component peaks in lumen pressure indicated that the duration of crassus contraction was similar to that of the tenuis musculature.

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Section: Physiological Findingssupporting

confidence: 76%

Spatiotemporal mapping of the muscular activity of the gizzard of the chicken (Gallus domesticus)

et al. 2013

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“…12 min (Duke et al . ; Duke ; Denbow ). The pellet is formed by intense contractions of the ventriculus, which also move the pellet to the base of the oesophagus.…”

Section: Discussionmentioning

confidence: 99%

“…Pellet formation in extant crocodilians is irregular (vs regular in birds) and the mechanism is very different from the specialized process in birds (Duke et al . ; Fisher ; Andrews et al . ).…”

Section: Discussionmentioning

confidence: 99%

The evolution of the modern avian digestive system: insights from paravian fossils from the Yanliao and Jehol biotas

O’Connor

Zhou

2019

Palaeontology

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The avian digestive system, like other aspects of avian biology, is highly modified relative to other reptiles. Together these modifications have imparted the great success of Neornithes, the most diverse clade of amniotes alive today. It is important to understand when and how aspects of the modern avian digestive system evolved among neornithine ancestors in order to elucidate the evolutionary success of this important clade and to understand the biology of stem birds and their closest dinosaurian relatives: Mesozoic Paraves. Although direct preservation of the soft tissue of the digestive system has not yet been reported, ingested remains and their anatomical location preserved in articulated fossils hint at the structure of the digestive system and its abilities. Almost all data concerning direct evidence of diet in Paraves comes from either the Upper Jurassic Yanliao Biota or the Lower Cretaceous Jehol Biota, both of which are known from deposits in north-eastern China. Here, the sum of the data gleaned from the thousands of exceptionally well-preserved fossils of paravians is interpreted with regards to the structure and evolution of the highly modified avian digestive system and feeding apparatus. This information suggests intrinsic differences between closely related stem lineages implying either strong homoplasy or that diet in each lineage of non-ornithuromorph birds was highly specialized. Regardless, modern digestive capabilities appear to be limited to the Ornithuromorpha, although the complete set of derived feeding related characters is restricted to the Neornithes.

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“…Larger items are torn into manageable pieces before being eaten. The undigested parts of prey are compressed in the stomach and egested orally as a pellet (Duke et al, 1976;Sturkie, 1986).…”

Section: Pellet Analysismentioning

confidence: 99%

Diet of tawny owls (Strix aluco) in relation to field vole (Microtus agrestis) abundance in a conifer forest in northern England

Petty

1999

J. Zoology

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The diet of tawny owls Strix aluco was determined from pellets and prey items in owl nests in Kielder Forest, a planted spruce forest in northern England. Field voles Microtus agrestis were their most important food, and formed the highest proportion of tawny owl diet in winter and early spring. Common shrews Sorex araneus, common frogs Rana temporaria and birds were taken more frequently in late spring and summer. Clear cuts, areas from which timber had been felled at the end of the rotation, provided the main ®eld vole habitat in the forest and remained suitable for voles for 10±15 years after re-planting. Field vole abundance was measured three times a year on numerous clear cuts throughout the study area using a vole sign index based on fresh grass clippings in runways. Tawny owls responded functionally to the 3 to 4-year cycles of ®eld vole abundance. In years when voles were scarce, adult owls took more common shrews and common frogs, as determined from pellet analysis. In contrast, more bird prey was fed to nestlings when ®eld voles were scarce, as determined from prey items in nests. The proportions of the main prey in nests changed over a 19-year period. More bank voles Clethrionomys glareolus and wood mice Apodemus sylvaticus occurred in every year after 1992 than in any year before this. Numbers of wood mice in owl nests increased signi®cantly throughout the study period, whereas bank vole numbers exhibited noncyclic, multi-annual¯uctuations that were unrelated to ®eld vole cycles. It is argued that¯uctuations in rodent prey re¯ected changes in rodent guilds in the study area; reasons for this are discussed. This is the ®rst study of tawny owl diet in spruce forests in Britain and highlights the value of such large-scale dynamic habitats for rodent populations and their predators.

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Mechanism of pellet egestion in great-horned owls (Bubo virginianus)

Cited by 28 publications

References 0 publications

Spatiotemporal mapping of the muscular activity of the gizzard of the chicken (Gallus domesticus)

Spatiotemporal mapping of the muscular activity of the gizzard of the chicken (Gallus domesticus)

The evolution of the modern avian digestive system: insights from paravian fossils from the Yanliao and Jehol biotas

Diet of tawny owls (Strix aluco) in relation to field vole (Microtus agrestis) abundance in a conifer forest in northern England

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