Bird feeding and Digestion
- Created by: ValentineDevil
- Created on: 14-03-19 10:13
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- Bird feeding and digestion
- Feeding
- Diets
- Carnivory
- Inverts
- Verts
- PISCIVORY
- INSECTIVORY
- Herbivory
- Various plants
- Seeds
- Fruits
- Nectar
- Niche separation, convergent evolution and alternative solution
- Omnivory
- Carnivory
- Reflected in bill and feet morphology
- Carnivores
- Longer beak = potentially tearing prey up (avoids being soiled much)
- Owl, short beaks, swallow prey whole- process bones (don't digests bones though)
- Cranial Kinesis
- Premaxillary bones of upper jaw articulated at craniofacial
- Allows upper beak to move at the same time as the lower jaw (pincer movement- cranial kinesis)
- Muscles opening lower jaw cause articular bone to pressurise the quadrate to rotate forward pushing palatine and jugal arches forward against the premaxilla
- Muscles pull the premaxilla downwards whilst the lower jaw is pulled upwards
- Muscles opening lower jaw cause articular bone to pressurise the quadrate to rotate forward pushing palatine and jugal arches forward against the premaxilla
- Allows upper beak to move at the same time as the lower jaw (pincer movement- cranial kinesis)
- Premaxillary bones of upper jaw articulated at craniofacial
- Carnivores
- Competition for food resources is also reduced by prey selection on the basis of size
- Specialisation in waders reduces competition for resources
- Redshank probes mud and picks off food from the surface
- Greenshank actively seeks fish and crustaceans in pools and water channels
- Oystercatchers use bill skills that have to be taught by parents to young
- Some smash shell with hammer blow; others open shell with sharp mandibles (by cutting through the muscle holding the two halves together)
- Cannot easily switch methods and takes months to be taught (but prising open shells is less effort) e.g. going from smasher to priser don't work as being a smasher blunts beak.
- Some smash shell with hammer blow; others open shell with sharp mandibles (by cutting through the muscle holding the two halves together)
- Diets
- Digestion
- Some birds lack a crop
- e.g. Ostrich have a proventriculus as storage structure rather than a crop
- Gizzard typically muscular to grind materials using ingested grit
- Variation in proximal alimentary tract associated with diet
- Small intestine
- Duoodenum; jejunum; illem
- Cloaca
- openings to large intestine, reproductive ducts and urinary ducts
- Bursa of Fabricus-lymphoid tissue produces B-cells
- Foregut fermentation in the Hoatzin
- Huge crop for fermentation of leaves
- Hindgut fermentation in Ostrich
- Some birds lack a crop
- Feeding
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