Chinese reading barn swallows

A group of barn swallows has built nests on the signs of these blocks of Mayfair Gardens in Tsing Yi. For some reason they have chosen to build their nests on the same Chinese character. Can they read Chinese? or do they prefer to have a (reading) light above their nest? Does the light attract insects for the birds to catch? Was the nesting technique passed on? Note the plastic ledge below the nests to protect residents from droppings. Apparently, Mayfair residents stopped the removal of the nests early last year by the Agriculture, Fisheries and Conservation Department (see link www.hkbws.org.hk/BBS/viewthread.php?tid=5185&page=1&a.... Obviously, the AFCD were acting in its capacity as anti-conservationists by destroying the nests, because the nests are neither agricultural nor fishery related.