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In respect of the debate on whether or not canaries possess Gizzards, and whether or not this organ requires grit in order to grind seeds for digestion, I have recently proved (reconfirmed) that:
- Canaries have large, heavily muscled fibrous gizzards
- The canary gizzard is lined with horn-like keratin
- The gizzard contains a mixture of seeds and grit.
On February 9th one of my young Fife Fancy hens was found dead in the aviary and I decided I would attempt a dissection, in order to see if there was any abnormality. The unflighted hen was about 8 months old and seemed healthy and well fed. I thought it had 'gone light', but in fact the bird was well-fleshed, had thick breast muscles and a layer of yellow fat around the flanks. So it must have been the cold - it was below freezing last night - though all the other birds are fine.I was not specifically looking for the Gizzard but it was so prominent that I could not avoid it. It is just as Robert Stroud describes in his Stroud's Digest of Bird Diseases: "a large, muscular organ taking up most of the left hand side of the bird's mid-abdomen". Initially, I thought it might be an oviduct with an egg inside, because it was very hard and egg-shaped. It was remarkably tough and hard - indeed cutting into it required some considerable effort. Apart from the heart and lungs, it was the most prominent organ in the body - it literally 'stuck out like a sore thumb'.
The photograph (above left) shows the organ cut open from the bottom of the Gizzard to the top of the Proventriculus (stomach). The food passes from the crop into the Proventriculus where it is coated with digestive acids. It then drops into the Gizzard. As you can see from the photo - the Gizzard is lined with a tough, horny, keratinous layer - which appears a dull yellow in the photo above. The speckled material is ground-up seeds mixed with grains of grit. I would estimate that less than 10% of the material in the gizzard was grit - I washed it out and filtered it through a coffee filter to examine it.
The dissection was carried out using nail scissors, a graphic-arts scalpel and toothpicks for probes. There was virtually no blood and the whole process took less than ten minutes. If you have never attempted it - I recommend you try it - but you will need:
- a DISSECTING KIT - or nail scissors and scalpel
- a good diagram of canary anatomy ( see below - After Bernard Poe - The Cage Bird Handbook)<>
- <>A good strong light
