MITES 231 



There are several Ixodes which are confined to birds. A cosmopoHtan 

 species, widely distributed in the nests of sea birds is the guillemot tick 

 (/. uriae). In Britain it is recorded from gannets, fulmars, guillemots, 

 puffins, curlews and so forth, from many coastal districts including 

 Devon, Yorkshire, the Fame Islands, St. Kilda and Shetland. On a 

 narrow ledge of cliff 400 feet above the sea and frequented during the 

 breeding season by tens of thousands of sea birds, Hewitt observed a 

 pair of/, uriae copulating beneath a stone, with four or five males stand- 

 ing by waiting their turn. The scene was described in a graphic 

 correspondence with Wheeler at the end of the last century, and makes 

 the reader sigh for the days when naturalists still found time to cultivate 

 letter writing as an art. 



Another species which parasitises sea birds is the shag tick (/. uni- 

 cavatus) which is confined to cormorants and shags and has been collected 

 near Plymouth, the Scilly Isles, the Cheddar Gorge and also certain 

 locations in Scotland and Ireland. /. canisuga is taken constantly from 

 the nest of the sand-martin in Britain, and continental writers consider 

 it is a separate species confined to this bird. Occasional records from 

 other bird hosts include /. caledonicus from crows, ravens, rock-doves and 

 a Greenland falcon from Scotland; /. brunneus, which is confined to bird 

 hosts in Europe, Africa and North America, and has been found once 

 in England on an owl ; and /. passericola which was discovered by Turk 

 on a Cornish house-sparrow nesting under the eaves of his own house. 

 There is also one record of Haemaphysalis cinnabarina from the stone- 

 curlew, and Hyalomma marginatum taken off a migrating rose-coloured 

 pastor on Fair Isle. 



It is interesting to note that in the U.S.A. when the numbers of the 

 snow-shoe hares are at low ebb the tick population of H, leporis-palustris 

 depends almost entirely on the ruffed grouse [Bonasa umbellus) as an 

 alternative host. 



The best known British example of the Argasidae, is the pigeon 

 tick [Argas reflexus). It lives in dove-cotes and pigeon lofts, although the 

 first record in this country was made from specimens caught in Canter- 

 bury Cathedral. At one time it was considered peculiar to "the dark 

 recesses of this time honoured fane." When pigeons are not available it 

 attacks other birds, such as sparrows and chickens. 



Ticks are very dangerous parasites. Their saliva which they pour 

 into the flesh of the host can be highly toxic, and the bite of one tick 

 may kill the host. Even their eggs contain poisonous substances which 



