CO NT EN T S

The Scottish Zoological Park; and other Editorial Notes

An Account of the Destruction of Methil Dock Gates by Marine Organisms (I llustrated)- J ames Ritcltie, 1J£. A., D .Sc.

O n the Decrease of Blackgame in -L eonora J effrey Rinto1tl and Evelyn V. Baxter ( Contimted from p. r 3) Bird Notes from Fair Isle, r 92 6- Surgeon Rear-Admiral .f. I:!. Stmlwu se

Notes on the Coccidce of Scotland- E. Ernest Green, F E .S., FZ. S. (Concluded)

Notes : A Large Dog Otter- Donald Ross, 44 ; Risso's Dolphin stranded in Caithness-Dr J ames Rite/tie, 6o ; Records of large Foxes-riarry fl. Bootlt, 6o; Eastern Les s~ r vVhitethroat on Hyskeir-J olm Bain, 44 ; Leach's Fork-tailed Petrel in D umfriesshire - riuglt S. Gladstone, 44 ; Wild Geese alightin g on Trees-Alec. T. Crmvjord, 6o; Further Records of breeding of Pochard at Dudclingston Loch- Dr J. Jl£. Dewar, 6r ; The Golden Eagle in Galloway-Sir Herbe1·t Ll£axwell, 62 ; Sweden to Britain : Migration of Rough­ legged Duzzard- Einar Lonnberg, Stocldwlm, 63 ; Young John Dory off \tV estern Inverness·shire-A. C. S tepltm, 44 ; Unusual Colour Variety of Haddock- Dr J as. Rite/tie, 62.

Book Notices

I PUB LISHERS' NOTE. 1 The Annual Subscription for 1927, payable in advance, 12s, 6d, post free,. l should be addressed to the Publishers, Oliver and Boyd, Tweeddale Court, . ) Edinburgh. 1 COVERS FOR BINDING "THE SCOTTISH NATURALIST.•• I Special Cloth Cases for Binding the 1926 Volume can be supplied at Is. 6d. each (by post rs. 9d.), by Oliver and Boyd, Tweeddale Court, Edinburgh.

t~R I N'l'~D BY Ol. l V&Il. AND UOYD 1 KDINBUROH. The Scottish ;-,!, Naturalist

No. 165] [MAY-}UNE

EDINBURGH: OLIVER & BOYD, TWEEDDALE COURT LONDON: GURNEY & J ACKSON, 33 PATERNOSTER Row

Prt'ce zs. 3d. Annual Subscription, payable in advance, r zs. 6d. post fru 88 THE SCOTTISH NATURALIST

THE SPIDER FA UN A OF THE WESTERN ISLA NDS OF SCOTLAND

By W. S. BRISTOWE, B.A., F.Z.S.

THE July of 1922 was spent cruising amongst the islands off the West Coast of Scotland in a 16-ton yawl, and most of the time spent ashore was given up ·to the collection of spiders. Ten islands were vi sited, but in most cases I only had a few hours on each, ow ing to my companions being yachtsmen rather than naturali sts, and in this time I naturally cannot claim to have made anything like an exhaustive collection on any of them. In the present paper I have combined all the scattered records of other coll ectors with mine to form a list of the spiders known up till now fr om these islands. The islands visited in chronological order were as foll ows:- The Isles of the Sea or Garvelloch Isles (outside ), Kerrera (Oban), Mull, Eigg, Rum, Skye, Priest Island and two of the off Ross and Cromarty, the Outer (Lewis and Harris), and the Shiant Isles (off Lewis). On the whole the spid er faunas of the different islands up the coast of Scotland appear to be very simila r. A ll the species found on the islands a re common on the mainland ) but the converse is far fr om being true. It is said that broadly speakin g the temperature fall s I oF. for each degree of latitude north or south of the equator, and that the same fall occurs for every 300 ft. rise in altitude. The faunas of mountain tops and arctic reg ions are often compared, but in these comparisons the lowness of the temperature is usually looked upon as the limiting factor. In actual fact the mnge of temperature is probably of equal importance or, to include another factor, namely wind, which would in practice be difficult to eliminate from our consideration, we can put forward another factor of importance which can be called "exposure." It is probable that both "temperature" and "exposure" as defined above SPIDE R FAUNA OF WESTERN ISLANDS OF SCOTLAND 89

I · act as limiting factors on different species, and, whilst reali sing that they cannot really be sharply differentiated, since the temperature varies appreciably with exposure, some notes foll ow which show the effects on distribution of these two roughly defin ed factors. W eb-building spiders are restricted to the more sheltered situations on the islands. T etragttat!ta extmsa is a wide­ spread and hardy species found from the Mediterranean to L apland and from temperate to arctic North A merica. This species is common on the islands but its relatives T. so!andrz'z' and T. pz'nz'cola, although found quite far north on the mainland, do not even approach the west coast of Scotland. These species a re most common ly met with in woods. . Of the 40-odd Epeirids recorded from arctic regions the majority are · restricted to the ma inlands of arctic Europe a nd A merica. No representatives at all of the family A ttidae we re found and the only one recorded in this li st is Euop!t1J'S erratz'cus, fr om A rran, which is otherwise common under stones on the mainland. A bout 20 species have been recorded from arctic regions, but these are chiefly fr om the mainlands of arctic Europe and A merica as in the case of the arctic A ttidae. The most successful forms are those which li ve under stones, etc. (Linyphiidae, Lycosidae), or in holes and burrows (Segestrz'a, Textrz~-o, Amau.robz'us and certa in Lycosid s). T hese will escape to a great extent both the li miting factors with which we are dealing. Major Hingston has shown * how on Mount E verest at IJ,ooo ft. the temperature beneath a stone va ried through only 1 2 ° F. during the t wenty-four hours, ·w hilst in the same period the temperature of th e air vari ed through 44° F. If our contention is correct, namely, that exposure is a n important limiting factor, in comparing t he faunas of mountain tops and the arctic, we shoul d make the com­ parison more especiall y with arctic islands. In the co urse of our cruise a number of mountain s were climbed, and although some were on the ma inland I give below a list of the species coll ected on each. On 8th July I climbed ·•· Geograj;ltical J ottrnal, May 1925. go THE SCOTTISH NATURALIST Halival (Rum). At the summit of this mountain, which is 2300 ft., several alpine-arctic plants grow, such as Silene acaulis and various Saxifrages. By turning over the stones amongst these I obtained the following spiders :- Robertus lividus. Crypha?ca silvicola. Leptyphantes zimmermannii. Troclzosa terrico!a. , pallidus. Tarentula pulveru!enta. Ceratinella brevipes. Nemastoma lugubre Centromerus prudens. (Opilionid). M acrargus abnormis. On the following day the weather forced us to stay in Loch Nevis, so we set out on foot to climb Ladhar Bheinn {3300 ft.). A very heavy mist descended on this mountain, however, so we had to content ourselves with a 2000 ft. one close to it. Here I collected the following :- Robertus !ividus. M acrm'gus abnormis. Leptyplwntes zimmermannii. N emastoma lugubre , erzca?us. (Opilionids). Centromerus prudens. Mitopus 11lorio. On the way down I found the webs of Epei1'a cornuta in a valley between the two mountains a few hundred feet from the summit. On 12th July we anchored in Broadford Bay (Skye) and I climbed Ben-na-Caillich (2400 ft.) which is one of the Red Hills. On the way up, at 1000 ft., I captured Lycosa traillii, which looks like an overgrown L. amentata. At the summit by turning over stones I collected the following:- Robertus lividus. M aro .falconerii. Leptyphantes zim11ler11lmmii. Neriene rubens. , w!tymperi. Pa?ci!omta g-lobosa. On our return journey we again came to Skye, anchoring this time in Loch Scavaig (25th July) and ascended one of the Cuillins, Sgurr Dubh-N ada-dheinn (3000 ft.). Conditions at the top of this mountain were very different. Vegetation, consisting of Silme acaulis, Saxifraga oppositifolia, etc., was very scarce, and the summit really consisted for the most SPIDER FAUNA OF WESTERN I SLANDS OF SCOTLAND gr

part of jagged bare rock. The best part of an hour's hunting produced but three species:-

l-f£!a£ra frz"g-ida . Coryphceus lw!mgnn£. ~Va!ckencera capito. When we reached Lochinver on 18th July (our turning point) we climbed Suilvin (2400 ft.). The following were collected :- Robertus lz'vidus. Pceci!oneta g!obosa. L eptyplzantes zz'mmermmmii. Tarmtu!a pulverulmta. Hz'! a ira fr£gida. N emastoma lugubre Caledonia evansii. (Opilionid). M acrargus abnormis. An examination of these lists shows us immediately that all the species are either forms which live under stones, or in the case of Tarmtu!a and Troc!tosa, burrow manufacturers which wander about on the ground when conditions are fa vourable. I noticed that just below the summit on the lee side of the mountains the number both of species and individuals always increased rapidly, and by comparing my results with those of Dr R. Jackson from some of the higher mountains of Scotland, one find s that two extremes of altitude exist in any given locality:- I. The extreme altitude at which a species will occur at the summit (limiting factor "exposure"). z. Extreme altitude below a summit (always greater than the last owing to the limiting fact or here being "temperature"). Three of the commonest species on the islands are JJ!Jeta meriance, Segestria senocu!ata, and Textn>c denticu!ata, None of these are found at high altitudes, nor do they ext end into the arctic (the nearest approach being Textn~1: in the Orkneys). It seems probable, therefore, that temperature governs the d istribution of these species. Lycosa pu!!ata, Tarentu!a pu!veru!enta, Robertus Nvidus and the Opilionid Nemastoma !ugubre on the other hand are limited to a greater degree by exposure than temperature. Their range extends into the arctic and they are to be found at fairly hig h altitudes on the Scottish mountains. The Lycosa does THE SCOTTISH NATURALIST not seem to like the summits, but Dr Jackson records it on the Cairngorms in sheltered situations at between 3000 and 3500 ft. Tarentula, Robertus, and Nemastoma have been collected on summits at 2400 ft., but in the Cairngorms below the summit at between 3000 and 3500 ft. The hardiest species appear to be .Hilaira fngida, COJyjJ!ta:us ltol11lgnni, Leptyplzantes whymperi, and Walckenaera rapito. The first two have been found at the summit of the Cuillins (3000 ft.) and Cairngorms (4300 ft.), and their range in the arctic includes various islands and is probably wide-1-Iilaim has been recorded fr om Greenland and J an Mayen, and Coryplzmus from Nova Zemlya, Spitsbergen, Bear Island, and J an May en. L eptyplzantes w!t;mzperi, which I found at the summit of Ben-na-Caillich (2400 ft.), was found by Dr J ackson at the summit of the Cairngorms (4300 ft. ), and on Ben Nevis above 4000 ft. wherever stones occurred amongst the snow. This species has been recorded fr om Greenland. Walckencera capito was one of the three species at the summit of Dubh-Noda-dheinn (3000 ft.) and Dr Jackson found it at the summit of Cairntoul (4200 ft.). This species has not been recorded from the arctic up to the present time. Before leavin g the subject of distribution I should like to draw attention to the similarity of the spider fauna of the western islands of Scotland to that of ( 1) the Irish Islands, and (2) the Norwegian Islands. Mr D. Pack Beresford records 108 species fr om Clare Island which is situated off the west coast of Ireland. His list includes all the species most commonly found on the Scottish Islands such as Seg-estria senoculata, Textrz~r denticulata, C1J'}Jhmca silviro!a, A maurobius simi!z'.s, Robe1'/us lz'vidus, M acrarg-us abnormis, Engone arctica, Tetrag-natha extensa, ll1eta meriance, M. seg-mentata, Lycosa pul!ata, T rocfzosa te1'ricola, Tarentula pulveru!enta, Xysticus cristatus, and the Opilionid N emastoma !ug-u bre. In addition three A ttids are recorded, namely, Neott reticulatus, Euoplzrys frontalis, and Heliophamts cupreus " in sheltered nooks facin g South or vVest." Conditions experienced on the Norwegian coast are very similar to those on the west coast of Scotland; when near SPIDER FA UNA OF WEST ERN ISLANDS OF SCOT LAN D 93

Bergen for a short time during the summer of 192 1 I made a small collection of 42 speci es, and this was sufficient to show how strikingly similar the spid er faunas of the two regions are. A ll were British species and the list included all the most typical Scottish forms such as :- Segestria senocu!ata, T extn:-r dentim!ata, LJ;cosa pzt!lata, T7'ochosa terricola, A maurobizts ft1Zest7'alis, Robertus !ividus, T !teridion bel!icosttm, Leptyphantes r.:immermamzii, En'g·one arctica, P ll?ci!o7teta g!obosa, Mac7'arg·us abnor111is, M eta meriam:e, and the opilionids Nemastoma !ztgttbre, lJ!!egabtt7ms diadema, and Obisizt71Z 11tztscorzt11l. The majority of spiders included in the li st which follows belong to the dominant section which have colonised the whole of the British Isles. A few are typical southern species such as D rassodes pubesce1Zs, Xysticus pini, LJ;cosa mmulata _- but only single records for these species exist, a nd it is possible that the identification is at fault. Some are northern species- En'gmte a?'ctica, T!Valckenmra crrpito, T !teridzo1Z bellicosum, and Lycosa traillz'i for instance-and three may be cl assed as arctic forms, namely Coryphll?us !tolmgreni, Hila ira fn'gida, and L eptjpltantes w!tymperi. I a m indebted to Mr E . J. Pearce and Mr H. B. Cott for small collections of spiders fr om Jura and Skye respectively, and, in addition, I am including an unpublished list of forty species made by Mr A. Pickard from the island of Colonsay and written into a copy of his uncle's paper on" The Spiders of Scotland," published in T!te Entomologist, 1877 (the late Rev. 0. P ickard-Cambridge). This paper has recently come into my possession and, seeing that Mr A. Pickard was in the habit of sending his uncle spid ers to identify, the Jist is in all probability perfectly trustworthy. A li st of species has been collected fr om the records of the late Mr W. E vans for A rran and Bute, which embodies the earlier records of F. L. Grant, 0 . P. Cambridge, and Professor Traill. In addition to solitary records for which references are given later, I include a li st of the spiders of St Kilda made by 0. P. Cambridge and records of Chelifers fr om some of the islands published by R. Godfr ey. With these additions the li st comprises 14 0 spiders (one ·-

94 THE SCOTTISH NATUR ALIST of which, 1/llz'cryphantes beatzts, Camb., is new to Scotland), I I Harvest spiders, and 3 Pseudo-scorpions. I am g reatly indebted to Dr A. Randell J ackson, who has himself made valuable additions to our knowledge of the Scottish Spid er Fauna, for examining practicall y all the spiders I collected and checking my identifications.

The initials inserted beside the different localities refer to the records and collections of the foll owing:-vV. S. B. = W. S. Bri stowe; 0 . P. C.= Rev. 0. P ickard-Cambridge ; H. B. C. = H. B. Cott; W. E . = W. Evans; R. G. = R. Godfrey; F. L. G.= F . L. Grant; J. E . H. = Rev. J. E. Hull; E. J .P. =E. J . Pearce; A. P. =A. Pickard; S imon= E. Simon ; Strand = E. Strand.

ARANEJE. Oonops pulcher, Tempi. . Bute (W. E.). Segestria senoculata, Linn .. Bute and Arran (W. E.); Colonsay (A. P.); Isles of the Sea, Eigg, K.errera, Priest Is., Summer Is., Lewis (W. S. B.). Drassodes !apidoms, Walck. Bute and Arran (W. E.); Colonsay (A. P.); Skye (H. B. C.); Eigg, Rum, Skye, Kerrera, Mull, Priest Is., Shiant Is. (W. S. B.). trog!odytu, C. L. K. Bute and Flannan Is. (W. E.); Mull (W. S. B.). pubescens, Thor. Arran (W. E.). A southern species. Ptosthesima petiverii, Scop. St Kilda (0. P. C.); Priest Is., Summer Is. (W. S. B.). Micaria pu!icaria, Sun d. . Colonsay (A. P.). C!ubioua trivia/is, C. L. K. Arran (W. E.) ; Orkneys (0. P. C. ); Lewis (W. S. B.). lwloserica, De Geer. Bute and Arran (F. L. G.); St Kilda (0. P. C.); Colonsay (A. P.) ?'ec!wa, 0. P. C. Bute (W. E.). diversa, 0 . P. C. Bute (W. E.). comta, C. L. K. Arran (W. E.). terrestris, \,Y estr. Bute and Arran (W. E.).

(To be continued.) NOTES 95

NOTES Large Dog Otter.-! was rather surprised to see in your last issue a dog otter weighing 21 lb. described as large, for in my article on the length and weight of otters in Tlte Annals of Scottish Nat1tral History (rgog), I gave the average weight of an adult dog otter as more than this, viz., from 2 r to 24 lb. At the same time, and also in the rgor vol., I gave instances of really large dog otters, viz., those on record of over 30 lb. in weight. The largest otters I ever came across were those living in the sea in the , and it would be interesting to have statistics of such from readers living or visiting these islands, for some of the skins I saw in farm­ houses and crofts there must have belonged to enormous otters of 30 or more pounds in weight-H. W. RomNSON, M.B.O.U., etc.

Gannets on the Bass Rock.-As I have not seen many notices concerning the time the first Gannet's eggs are laid on the Bass Rock, it may be of interest to state that the first egg was found this year on 1st April, which is earlier than usual. As I have, as yet, had no returns fr om the roo young marked there with rings last year, perhaps your readers will examine· any dead Gannets they may come across for rin gs and record the same, especially so as the only two records of those marked there in a form er year are somewhat puzzling.-H. W. RoBIN SON.

Hawfinch nesting in Kirkcudbright.-On 2 rst April, I was handed a I-Iawfinch which bad been picked up dead near Dalskairth, Maxwelltown, Kirkcudl>right. Last year (1926) a pair of these birds nested at Dalskairth and hatched their young, which, however, were destroyed just L>efore they could fly.-Hucu S. GLADSTONE.

Great Snipe in Forfarsbire.-A rushy marsh at E lli ot is a favourite resort of snipe on arrival fr om oversea. On 13th August last what at first sight seemed to be a very small W ooclcock feeding along the muddy margin of the marsh proved to be a Great Snipe. Several Common Snipe were partly visible in the vegetation on th e opposite side, thereby enabling the two species to be compared. Probably it was the same bird which was seen again on the r6th on a grassy plot occasionally subjected to flooding, and fin ally on the 2oth at the marsh.-DoUGLAS G. H uNT im, Arbroath.