Ticking Crow
One of my regular walks with Jess is across the neighbouring croft 81 at Torbreck to a small hill west of my house. The lower summit of this hill (NC082242), which overlooks two nameless lochs (photo 1), is used by hooded crows as a perch and I often come across their pellets.
I was on this hill on 28th September 2023 and picked up a pellet (photo 2). A close look revealed the presence at one end of the remains of large tick (photo 3). Intrigued, I passed the pellet on to Ian Evans for dissection under a low-power microscope.
His report on the contents was as follows: the remains of four ticks, three large and one small; fragments of beetle elytra and legs, probably from ground beetles; numerous skins of berries, probably rowan, with a few seeds of the same; three or more small stones up to 3mm diameter; all embedded in a mass of pale fibres, later confirmed as sheep’s wool.
Ticks
The best-preserved tick was about 3mm long, and from the relatively small size of the dark scutum or shield at the anterior end, probably a gravid female of the common sheep tick or castor bean tick Ixodes ricinus. This is the commonest of the 26 species found in the British Isles.
Quoting from the definitive text (Hillyard 1996), ‘Many different kinds of wild and domestic animals serve as hosts for Ixodes ricinus; this tick will also attach to humans’. Hosts include ‘sheep, cattle, deer and dogs’ and the ‘nymphs and larvae also feed on small mammals (mustelids and downwards in size), birds of many kinds, e.g. blackbirds and warblers, and even reptiles’. We have several times seen them on common lizards, as in the old quarry opposite the breakwater in Lochinver (NC087221; photos 4-5).
More to the point, perhaps, ‘birds, e.g. starlings, crows and chickens, eat many engorged ticks which have dropped to the ground’. A case of the biter bit?
Reference. Hillyard, Paul D., 1996. Ticks of North-West Europe. Shrewsbury: Field Studies Council
Gwen Richards
Photos by Gwen Richards