Editing Corn crake (section)

===Voice===
{{listen|filename=Crex crex, July 2010.ogg|title=Corn crake|pos=right|description=Male's advertising call}}
On the breeding grounds, the male corn crake's advertising call is a loud, repetitive, grating ''{{not a typo|krek krek}}'' normally delivered from a low perch with the bird's head and neck almost vertical and its bill wide open. The call can be heard from {{convert|1.5|km|mi|abbr=on}} away, and serves to establish the breeding territory, attract females, and challenge intruding males. Slight differences in vocalisations mean that individual males can be distinguished by their calls. Early in the season, the call is given almost continuously at night, and often during the day, too.<ref name="taylor320" /> It may be repeated more than 20,000 times a night, with a peak between midnight and 3&nbsp;am.<ref name="cocker" /> The call has [[sexual selection|evolved]] to make a singing male's location clear, as this species hides in vegetation.<ref name="Osiejuk" /> The frequency of calling reduces after a few weeks but may intensify again near the end of the laying period before falling away towards the end of the breeding season. To attract males, mechanical imitations of their call can be produced by rubbing two pieces of wood or ribs, one of them with notches,<ref name="Boswall" /> or by flicking a credit card against a comb or [[zipper|zip-fastener]].<ref name="cocker" /><ref name="Mason" /> The male also has a growling call, given with the bill shut and used during aggressive interactions.<ref name="taylor320" />

The female corn crake may give a call that is similar to that of the male; it also has a distinctive barking sound, similar in rhythm to the main call but without the grating quality.<ref name="Ottvall" /> The female also has a high-pitched cheep call, and a ''{{not a typo|oo-oo-oo}}'' sound to call the chick. The chicks make a quiet ''{{not a typo|peeick-peeick}}'' contact call, and a chirp used to beg for food.<ref name="taylor320" /> Because of the difficulty in seeing this species, it is usually [[census]]ed by counting males calling between 11&nbsp;pm and 3&nbsp;am;<ref name="bibby" /> the birds do not move much at night, whereas they may wander up to {{convert|600|m|yd|abbr=on}} during the day, which could lead to double-counting if monitored then.<ref name="Hudson" /> Identifying individual males suggests that just counting calling birds underestimates the true count by nearly 30%, and the discrepancy is likely to be greater, since only 80% of males may call at all on a given night.<ref name="Peake" /> The corn crake is silent in Africa.<ref name="newman" />