250 FLEAS, FLUKES AND CUCKOOS 



infested with the hen flea. Two other species, G. nidicola and G. 

 buyssoniy are recorded from owls' and hawks' nests in Britain. Some- 

 times the adults develop a perverted taste and chew the feet of sitting 

 birds. However Gnathoncus is generally modestly represented compared 

 with its prey. A flycatcher's nest harboured 170 specimens, a great 

 tit's 58, a chaffinch's 34, and 14 were taken by Spittle from an owl's 

 nest. Three other British histerids found in birds' nests are Dendrophylus 

 punctatuSy D. pygmaeus, and Hister merdarius. In addition to the predatory 

 beetles there are numbers which perform a useful function by scaveng- 

 ing in the nests of their hosts. We have already mentioned the beetles 

 Trox scaber and T. scabulosa which are very common in nests of birds of 

 prey where they feed on bones and hides. Over 100 specimens have been 

 recorded from one nest. Beetles of the family Lathridiidae, such as 

 Enicmus minutus, which feed on fungi both as adults and larvae, are 

 frequent occupants of a wide range of birds' nests, and act as scavengers. 

 About 40 species of beetles have been recorded from hirundinid nests 

 in northern Europe, but the jackdaw can probably boast the greatest 

 attraction for Coleoptera. Over 50 species have been recorded from its 

 nest alone. Nordberg, by a somewhat abstruse calculation, found there 

 were 280 beetles per cubic decimetre of jackdaw nesting material ! 

 Few birds, however, harbour a host-specific beetle. Probably the only 

 avian host in Britain thus distinguished is the sand-martin. 



Even more peculiar is the fact that the sand-martin is parasitised by 

 a host-specific tick, Ixodes canisuga. As we have seen (p. 229) ticks are 

 rarely host-specific — and in this respect, as well as many others, the 

 sand-martin is unique among British passerine birds. The mite fauna 

 of birds' nests is extensive, consisting of species which are parasites of the 

 host or other nidicoles, or are scavengers and plant eaters. The martins 

 have several species which are peculiar to them. 



Certain clothes moths are also found in birds' nests ; Tinea pellionella 

 is a common species in martins' and sparrows' nests. The larva feeds on 

 the lining but it also chews up expensive materials such as carpets, fur 

 coats and cushions in the houses on which the birds have built their 

 nests. A predator of the larva, the window fly (Scenopinus fenestralis) has 

 occasionally been recorded from nests. Another related moth, T, lapella 

 (see tail-piece of Chapter 2, p. 19), is an obligate commensal of certain 

 passerine birds like the hedge-sparrow and thrush. The larva also feeds 

 on feathers, and although there are presumably many other sources of 

 keratin available this moth has up till now been found only in nests, and 



