G Glossary of bird terms
the gape flange on juvenile house sparrow yellowish region @ base of beak. gape the interior of open mouth of bird. width of gape can factor in choice of food. gape flange the region upper , lower mandibles join @ base of beak. when born, chick s gape flanges fleshy. grows fledgling, gape flanges remain swollen , can used recognize particular bird young. gizzard also ventriculus; gastric mill; gigerium. specialized stomach organ found in digestive tract of birds constructed of thick muscular walls used grinding food, aided particles of stone or grit. birds gizzards swallow food , store in crop if necessary. food passes secretory part of stomach (called glandular stomach, , proventriculus or true stomach ). food passes gizzard can ground swallowed stones , passed true stomach, , vice versa. bird gizzards lined tough layer made of carbohydrate-protein complex called koilin, protects muscles in gizzard. gleaning specialized cases: foliage gleaning; hover-gleaning; crevice-gleaning. strat...