A large collection of continuous glass bundles which is tangled up and will not run through the guide eye into roving creel. In the field, a large tangled collection of roving which does not run through the tube or guide eyes to the chopper.

Accumulation of thread caught between the embroidered item and the needle plate, often caught in the needle plate hole and hook assembly. The birdnest starts out by the thread being caught underneath the needle plate in the hook assembly or related parts.

gather birdnests; "They went birdnesting in the early morning"