Independent of the notes of each species, as already given, numerous flocks of small birds were seen passing the stations, but too far distant to determine the species. This was specially the case at the Spurn, on Dec. 3rd and 8th; at the Cockle, on Oct. 9th; and at the South-sand Head, on Sept. 20th. At the Kentish Knock, on Nov. 20th, half-a-dozen small birds came on board at midnight, which, from the written description in the margin, were probably Greenfinches. It is, however, impossible to give even a guess at another species which visited another lightvessel on Sept. 20th, "Fifty very small birds—in fact, the smallest of British birds—like a Sky Lark, but a deal smaller." From the date, they may have been either Titlarks or Flycatchers.
No rare migrants have been noticed, but this was scarcely to be expected. In this respect the budget of notes supplied by that veteran ornithologist Herr Gätke bears a striking contrast to our east coast reports. On that small island, so favourably situated for observation, Mr. Gätke has trained up quite a host of practical observers, and any rare visitant will have to be very sharp if it succeeds in escaping detection. Quoting from Mr. Gätke's letter dated Dec. 22nd, we have, on Sept. 17th, Sylvia fuscata, though not got; Anthus Richardi on the 18th; A. cervinus on the 20th; Picus leuconotus on the 21st; then some days S.W. with rain and no birds; 26th, calm and clear, Emberiza pusilla; 27th, E.N.E., Anthus Richardi, Emberiza pusilla (two shot), E. aureola (seen); 28th, E. pusilla (two seen), E. rustica (one shot); 29th, Sylvia superciliosus (one); 30th, Emberiza pusilla (one); Oct. 1st, E. pusilla (one); Nov. 2nd, 3rd and 4th, westerly winds and nothing, but daily some Parus ater; on the 5th, again, Anthus cervinus (seen and heard); northerly winds, sometimes N.E. on the 8th, a Leaf Warbler seen at close quarters, but not procured by Aeuckens, the Heligoland birdstuffer, which Mr. Gätke feels tolerably certain was a very rare visitant; the same day there were two or three E. rustica, and one each of A. pusilla and A. cervinus. The rare Leaf Warbler was again seen on the 9th, but could not be obtained; an Emberiza rustica was also seen. On the 10th, E. pusilla shot and E. rustica seen. On the 12th, Muscicapa parva and Motacilla lugubris, which latter comes there rarely in autumn. On the 14th, Sylvia superciliosus was shot by Mr. Gätke's eldest son, and two more were seen by Aeuckens in a garden where shooting was not permitted. On the 18th, one very fine E. pusilla shot. On the 20th Lestris affinis was seen close by, but not shot, as it would have fallen in the sea and drifted away. This is the third, if not the fourth, known occurrence of the Siberian Herring Gull at Heligoland. On the 24th a large Redpoll was shot, which Mr. Gätke thinks can only be the Greenland bird, Linota Hornemanni.
A summary of the various returns show that four species, Larks, Starlings, Rooks and Hooded Crows, in the order given respectively, far outnumber any other, and of these four the Lark far exceeds the rest in migratory numbers. As a rule, the lines of migration followed have been from E. to W., or S.E. to N.W. direct on to the English coast. To the middle of October we find birds rarely coming from points north of east; after this date they appear to come occasionally from directions north of east, between east and due north. The line of migration of the Anatidæ has been from north to south, crossing the line of the Insessores at right angles.
There is one remarkable exception to the general rule of an east to west route in the case of the lightvessel on the Galloper Bank, forty miles S.S.E. of Orfordness. All entries in this return show birds passing to the E. or S.S.E. or S.E. during October. We can only account for this anomalous line by supposing the birds which cross the Galloper have previously struck the English coast at some higher latitude, and after skirting the coast line shot off again somewhere near Orfordness and crossed the North Sea to the Belgian and French coasts between Nieuport and Dunkerque. On Nov. 24th a great quantity of Larks and Starlings passed the Galloper towards the N.N.E, a line which if persevered in would eventually bring them to the Dutch coast.
At the East-side from the 2nd to the 5th of November flocks of "Crows" were observed passing from the S. to the N., or from the French to the Suffolk coast. The great body of the immigrants during 1879 have crossed at the more southern stations, the four lightships on the Goodwin Sands, also the Nore, the Shipwash and Kentish Knock showing a constant and continuous stream on to the south-east coast. These birds would all cross at the narrowest part of the North Sea directly from E. to W. to the English coast. The long prevalence of north-westerly winds in October and November may to a great extent have deflected the lines of migration much farther to the south than is generally the case.
Migrants have passed the stations at all hours of the day and night, flying at no great altitude and in almost all winds and weather. When the nights are dark and cloudy, no stars appearing, in rain, fogs and snowstorms, flocks of birds during the night migrations will crowd round the lanterns of the lightships; many strike the glass and are killed, falling on deck or pitching overboard. On these nights birds will often remain for hours in the vicinity of a light, circling round and round, evidently having lost their way; at the first break in the clouds, the stars becoming visible, or the first streak of early dawn, they will resume their flight to the nearest land.
The "great rush" of immigrants was from the 12th to the 23rd of October. The "final rush" took place just preceding and during the first burst of winter, early in December.
The occurrences when birds travel dead to windward are very rare indeed, and then only with light winds. In the great majority of cases birds migrate flying within two to four points of the wind, sometimes with a "beam" wind, or even a point or two "abaft of beam." If the wind changes during the actual passage, birds will change the direction of their flight to suit the wind. Thus at the Shipwash, on Oct. 16th, from 9.50 a.m. to 1.20 p.m. the wind was N.N.W., flocks constantly passing from S.E. to N.W. from 1.20 to 3.20 p.m. the wind blew from N.N.E., and the birds passed S.S.E. to N.N.W. If subsequent observations should prove the correctness of this rule, it will go far to account for all the irregularities of migration—the "why" birds are seen in great numbers in one year in any locality, and perhaps absent altogether in following seasons.
Subsequent to the writing of this report I have received several communications showing a large and very remarkable influx of immigrants on to the east coast of England in January and the first fortnight in February, 1880. On Jan. 24th great numbers of Fieldfares were seen near Spurn Point, between Easington and Kilnsea, and since this date they are reported as very numerous in the locality; with the Fieldfares came many fine old cock Blackbirds. In North-East Lincolnshire, also, during the last fortnight in January I saw many very large flocks of Fieldfares, apparently entirely composed of old birds; before this time scarcely any had been seen. Mr. Gätke writes from Heligoland:—"T. pilaris all January, through night from 10th to 11th, great many; also Oystercatchers and other waders coming from the E; also from 21st to 24th, the same." These dates agree very well with the time of their arrival on our east coast. Short-eared Owls arrived in some numbers at Spurn in the last week in January. A very large flock of Snow Buntings was seen on the 8th February. On the Lincolnshire side I noticed an immense flock of the same species, fresh arrivals, on the 5th; and on the 11th thousands, also hundreds of Larks. This final and third "rush" of immigrants so late in the winter is curious, and may perthaps be explained by the comparatively milder winter over Northern Europe, compared with what we have experienced in the central and southern zones of Europe. We have indeed a recent precedent for this in the winter of 1877-78, when, after a long continuance of mild weather in Scandinavia, a sharp and sudden outburst of real winter drove the Fieldfares, as Mr. Gätke says, over Heligoland, on the night from the 27th to 28th January, in "countless flights."