Mabch, 1902.] 



KNOWLEDGE 



53 



in this ujii;nitioii of the skvlark from Central Euroi)o. the 

 birds proceed westward and j)Ossiblj northward from tlieir 

 breeding grounds to reach their winter quarters. This 

 immignitiou begins usually at tho end of September, 

 reaches enormous proportions in October, and practically 

 ceases at the beginning of November. The birds striice 

 our east coast in extended formation, reaching from the 

 Humber, and even the Tees, to the south coast. Some idea 

 of the magnitude of this influx may be gathered from the 

 fact that in four years out oi the eight covered by the 

 enquiry, skylarks were observed to arrive by this route 

 on over twenty days in each October. 



An interesting fact in connection with the immigration 

 from Central Europe is, that the passage across the North. 

 Sea is invariably performed in the day-time, the birds 

 arriving from dawn until noon. Mr. Clarke does not 

 make it quite clear whether the whole journey is sometimes 

 performed in daylight or not, but since all important 

 migrations are begun in the evening it seems that these 

 birds have been travelling all night. Sometimes, however, 

 they do not arrive before 3 p.m., and then the very rcmark- 

 alile, but not very uncommon, spectacle may be witnessed 

 of two streams of birds of the same species migrating iu 

 opposite directions. For at this time in the afternoon our 

 home-bred skylarks are starting on their journey to their 

 winter quarters on the Continent, and their line of flight 

 is actually crossed by the skylarks coming from Central 

 Europe. 



The coast, however, is not the ultimate destination of 

 these travellers. On their arrival they disperse in various 

 directions. Many intend to spend the winter somewhere 

 iu our islands, and of these some go inland and scatter 

 over the eastern, southern and midland counties of England, 

 but the majority proceed southward along the east coast 

 and then westward along the south coast. Arrived at 

 Land's End, many continue on a westerly and northerly 

 course and so reach Ireland. Largo numbers of these sky- 

 larks, however, are merely birds of passage with us, and 

 on arriving in the west of England, they cross the channel 

 at various points to the French coast. 



The return of these birds to their breeding haunts 

 iu Central Europe in the spring comes very little under 

 observation compared with the inflowing streams iu 

 autumn. The reasons for the want of observation are easily 

 explained. To begin with, the number of skylarks has 

 been eni>rmously lessened V>v the ravages of winter as well 

 as by the dangers of the long journeys. Then the birds 

 set out from the coast in the evening, and on starting rise 

 to such a height that they are seldom attracted by the 

 lanterns of the lighthouses as they are when descending as 

 they near the coast. But enough observations have been 

 recorded to show that the return is made on much the 

 same lines as the arrival, and that the movement begins iu 

 February and is continued until the end of March, the 

 28th being the latest day recorded. 



There is yet another perfectly distinct migration of the 

 skylark to be observed in Great Britain. This movement 

 is concerned with the birds which summer in Scandinavia 

 and seek our shores iu autumu. The vanguard of these 

 northern skylarks arrives very punctually in the first week 

 in October, ami the whole migration is usually compressed 

 into four weeks, so that, as a rule, it ceases early iu Novem- 

 ber. By this route, again, enormous numbers of skylarks 

 reach our shores, but they strike the coast further north 

 than those from Central Europe. Some ])ass down the 

 coast, and leave us for warmer dimes, but the majority 

 disperse themselves over our islands, some reaching the 

 Hebrides and replacing the home-bred birds which have 

 already left their summer haunts. In mild seasons, 

 during the third week in Februarv, the birds begin to 



return to the north by the routes taken in autumn, and 

 throughout March, especially after the middle of the 

 month, there is much evidence of their departure. 



The above-mentioned movements of the skylark (viz. : 

 Emigration of home-bred Iiirds ; immigration of winter 

 visitors and birds of passage from Central Europe ; 

 immigration of winter visitors and birds of passage from 

 Northern Euro]5e ; and the return journeys) are those of 

 a strictly migratory character which have been observed 

 in the British Islands ; but reference must be made to 

 other niiivi'incnts, which depend entirely on the state of 

 the weather. The skylark obtains the whole of its food 

 on the ground, and hence a fall of snow or a prolonged 

 frost drives it to change its quarters. Should the cold be 

 of short duration, the movements of the skylarks are 

 merely locil. and the birds soon return to their former 

 haunts. Should, lujwever, the adverse conditions continue 

 and become general, the movement becomes widespread 

 and almost universal. " This effect," says Mr. Clarke, " is 

 especially ]>roduced by great snowstorms, when the 

 number of fugitives is so vast that people wonder wh<'ie 

 such prodigious multitudes can come from, as they throng 

 towards the coast, and particularly the milder siuth-west 

 coast of England .... though many undoubtedly 

 cross the Channel and others proceed to Ireland." 



THE SWALLOW. 



The familiar Swallow may be taken as a typical example 

 of a summer resident in the British Isles. Although its 

 migrational movements in this country are much more 

 simple and more easily followed than those of the skylark, 

 it must be borne in mind that the birds which migrate to 

 and from our shores are not all summer residents. Some 

 of them are merely birds of passage passing through on 

 the way to their breeding stations in Northern Europe. 

 The winter quarters of the swallow are known to be in 

 Africa, chiefly to the south of the Great Desert. 



In dealing first with the spring immigration of swallows, 

 which come to breed in this country, it should be stated that 

 Mr. Clarke's material is so complete that he is able "to 

 speak with authority as to the date of the swallow's 

 successive arrivals on our shores, and also to trace with 

 some degree of acciu'acy its gradual spreading over the 

 couritry, which has hitherto been a desideratum." 



A few solitary birds annually appear in March, but it is 

 not until April that the vanguard of the host arrives. 

 These early arrivals are either single birds or pairs. About 

 ten days after the first comers, swallows appear iu some 

 numbers, and the influx proceeds throughout the rest of 

 April and the first half of Maj'. Those which arrive later 

 are birds of passage proceeding to higher latitudes. 



The first arrivals appear at different dates in different 

 parts of our islands, aud the appearance of swallows on the 

 western seaboard, not only of the South of England but 

 also of Scotland, is always some days in advance of their 

 arrival on the east coast. Mr. Clarke has drawn up 

 the following table of first arrivals: For south-western 

 England, the beginning of the first week of Ajiril ; for 

 Ireland the end of that week ; for south-eastern England, 

 early in the second week; for south-western Scotland, the 

 end of the same; for south-eastern Scotland, the middle of 

 the third week; for northern Scotland, the fourth week; 

 and lastly, it is not till the second week in May that the 

 few swallows which resort to Orkney reach their des- 

 tination. 



As regards the manner in which the migration is per- 

 formed, Mr. Clarke writes : — " Swallows are described as 

 airiving on our southern shores during the day-time, 

 chiefly in pairs, but sometimes as many as six or seven 

 together, aud flying low over the sea. The immigration 



