Beach-combing

An astonishingly warm day today, just the sort of day for a spot of beach-combing.

The main photograph shows the shells of a dead cockle Cerastoderma edule. The shell is ornamented with both radial ribs and  circular rings. The circular rings are growth rings and can be used to age the cockle. A little new shell material is added to the edge of the shell every day and so you can, in theory, age a cockle to the nearest day.

The extra is of a broken upper bill of a bird, probably a heron. The main feature of interest is that the bone is hollow with criss-crossing struts or trusses for structural strength. This provides great strength and rigidity for a minimum weight; just what is needed in a flying animal.