Yorkshire Naturalists at Skipwith. 
165 
coloured deposit of ferrous carbonate caused by the activities of iron 
bacteria was observed in a very acid ditch, thus showing that these 
organisms can tolerate appreciable acidity. 
Vertebrate Zoology (C. F. Procter) : — The day was a very interest- 
ing one to the Vertebrate Section, as this common comprises a number of 
differently conditioned shallow ponds. On most of these the Black- 
headed Gulls have formed colonies, but they have been very wisely 
prevented from monopolising the whole of the available sites. The late 
Lord Wenlock unreservedly protected these beautiful birds in the later 
years of his life, and the effect of the absence of restriction was such 
that at one period they overshadowed all other bird life, and between 
800 and 1,000 pairs, as far as could be judged, occupied the common. 
The little tussocky islets that were essentially favoured were quite 
inadequate for their needs, and they actually built along the narrow 
plank bridges and all round the edges of the ponds. At the present time, 
other species are given a chance, which is very much to the good of 
Skipwith Common as a bird sanctuary. The following birds were seen 
and reported : — 
Black-head Gull, Mallard, Shoveller Duck, Teal, Coot, Water Hen, 
Carrion Crow, Rook, Jackdaw, Pheasant, Curlew, Redshank, Snipe, 
Ring Dove, Turtle Dove, Cuckoo, Green Plover, Swift, Swallow, House 
Martin, Thrush, Blackbird, Skylark, Chaffinch, Chiff-chaff, Whinchat, 
Sedge Warbler, Willow Warbler, Pied Fly -catcher, Tree Pipit. The 
Grasshopper Warbler was heard at Bishop Wood by some of the party 
who visited that place. 
The keeper, Mr. J. Morris, reported that he had observed a pair of 
Pintail Ducks and that the Shelldrake and Pochard were on the common. 
He also reported that the Nightjar had arrived during the past week. 
There was ample evidence of foxes and rabbits. One occurrence of 
the grass snake was reported, and the common lizard, Lacerta vivipura, 
was seen many times during the day. 
Entomology (J. M. Brown) : — The visit was rather early in the 
season for adult Heteroptera to be about in great quantity, and beating 
was not very productive. From Scot’s fir Gastrodes ferrugineus L. was 
obtained in some number, and from birch, a single Elasmucha grisea L. 
General sweeping yielded Liocovis tripustulatus F., Monalocoris filicis L., 
and Stenodema calcaratum Fall., while among the roots of heather occurred 
Scolopostethus decor atus Hahn., and on damp soil, Acanthia saltatoria L. 
The Homoptera were represented by Delphacodes pellucida Fab., and 
D. discolor Boh. swept from grass. 
Hemerobius nitidulus Fab., beaten from Scot’s fir, was the only 
Lacewing noted, and Limnophilus grisea L. and L. auricula Curt, resting 
on birch, represented the Caddis-flies. A single species of Stone-fly, 
Nemoura variegata Oliv., was moderately numerous, and one example 
of Dragonfly, Pyrrhosoma nymphula Sulz., in teneral colouring, was 
handed to me by Mr. Bramley. Elipsocus westwoodi Mc.L. was plentiful 
on sallow. 
To these notes Mr. H. Oste'ide contributes the following list of 
Coleoptera — 
Cicindela campestris L. 
Calathus cisteloides Pz. 
Patrobus excavatus Pk. 
Bembidium lampros Hbst. 
Tachinus marginellus F. 
Quedius fuliginosus Grav. 
Philonthus firnetarius Grav. 
Cytilus vartus F. 
Onthophiluis sriatus F. 
Dolopius marginatus L. 
Cyphon variabilis Thunb. 
Phyllobius pyri L. 
Anoplus plantar is Na j z. 
Orchestes salicis L. 
Apion violaceum Kirby. 
Rhynchites betulce L. 
Chrysomela staphylea L. 
Lochmcea suturalis Th. 
Chalcoides fulvicornis Fabr. 
Adalia bipunctata L. 
Coccinella j-punctata L. 
1933 July 1 
