May 26, 1910] 



NA TURE 



175 



listening to her call. And now he, too, changed his 

 cry, his voice seemed to break, and the adult yelp 

 . . . burst from his throat. The Eagles called to 

 each other, yelp answered yelp. . . . The young Eagle 

 gazed around him . . . spread out his giant wings 

 and vanished for ever from my sight among the 

 ledges below. . . . The Eaglet had left the nest and 

 had flown." 



This record is illustrated by thiity-two beautifully 

 clear plates, reproduced from the author's photo- 

 graphs, which are splendid achievements when the 

 difficulties of the situation and of the weather are 

 considered. In them the eaglet's history is depicted 

 from the ^^^ to the day when it takes flight from 

 the nest. Plate 18, "■ Father and Child " (Fig. i), is 

 here reproduced by courtesy of the publishers as a 

 specimen of the series, ever\' one of which is worthy 

 of the ornithologist's careful study. 



(2) This is the fourth report of the Migration Com- 

 mittee of the British Ornithologists' Club, appointed 

 in November, 1904, for the purpose of collecting and 

 collating evidence regarding the arrival and dispersal 

 within England and Wales of some thirty strictly 

 migratory species which winter abroad and nest 

 within these limits. These reports are based on 

 the records supplied by voluntary observers on land 

 and on off-shore lightships and lighthouses, who have 

 filled up and returned to the committee schedules of 

 questions issued to them. Each report deals with 

 the spring immigration and the chief autumn move- 

 ments of the scheduled birds, the one under notice 

 being for the autumn of 1907 and the spring of 190S. 

 It opens with a summary of the weather reports from 

 March to May, 1908, the period covering the spring 

 immigration. The second section details the 

 chief movements observed at the lights during 

 the same period, and indicates the moon's phase 

 and the direction of the wind on each occa- 

 sion. Next are discussed the schedules of the 

 thirty-three species, individually, each accompanied 

 by a map, on which are plotted the more 

 important data of their arrival and dispersion. Supple- 

 mentary to this, the main iand imiportant portion of the 

 report, are recorded observations on birds not specially 

 scheduled. The migrator\- movements of the autumn 

 of 1907 are then dealt with, but we regret to find no 

 meteorological notes associated with this section, in 

 which the weather conditions have a special bearing 

 on the causes which impel the birds to start on their 

 autumn journey southwards. A statement of the days 

 and nights on which migration was recorded at the 

 lights between Spurn Head and the Bristol Channel 

 during the autumn of 1907, and a list of the observers 

 close the volume. 



The report calls for little at this stage in the way 

 of discussion, as it is not a final dieest, but a further 

 instalment of data towards the elucidation of the great 

 mvstery of bird-life, compiled with great care and 

 labour, for which ornithologists generally will desire 

 to offer their grateful thanks to the committee. Nor 

 is there much in its contents deserv-ing of criticism, 

 except, oerhaos, to direct the editor's attention to the 

 rather irritating omission from the maps of the 

 elucidatory legends which aopeared on those of some 

 of the earlier reports, especially as no explanation is 

 given in the text of the various symbols emploved in 

 any of the maps in the report under review. In the 

 two maps devoted to the "swallow." in the first re- 

 port, for instance, we find that a date within a circle 

 was employed as the symbol for " 2nd migration " on 

 the one map, as well as for "5th migration" on the 

 other ; while on that for " the nightjar " it stands for 

 "main migration." In other maps the "5th migra- 

 tion " is represented bv the date within a triangle. 

 It would be a trreat advantage if in ever}- map the 

 NO. 2 II 7, VOL. '^'^ 



same symbols were used to indicate the same migra- 

 tion. Failing this, those used in each map should be 

 printed upon it. On the map devoted to the black- 

 cap in this report (p. 74), we find circles, squares, 

 ellipses, and parallelograms, with no explanation of 

 their import, the sole legend being ■■M = May; all 

 other dates are in .April." Further, on consulting the 

 letterpress of the schedule for the same bird (p. 75) we 

 read, " the earliest arrivals were reported from Glou- 

 cestershire on the loth, 14th, and 21st of March, and 

 these were followed by a pair in Devonshire on 

 the 28th " ; yet on referring to its map we discover no 

 entr\- for any of these dates in the shires named ; nor 

 is the bird's earliest appearance in Wiltshire, on 

 April 6, indicated on it, yet that of the 13th is 

 entered, although it is stated in both cases 

 j that '■ the great proportion of the records were of 

 j single birds." .Again, the same sjsecies is noted at St. 

 J Catherine's light on April 10 and 11, and the date is 

 1 plotted on the map unenclosed by a line^ its occur- 

 rences for April 27-30 are surrounded by an ellipse, 

 while the . dates of birds arriving four days 

 later are enclosed in a parallelogram ; yet the two 

 records can hardly, we imagine, be assigned to a 

 separate migration. Without, therefore, a legend or 

 explanations in the text it is difficult to follow comfort- 

 ably the map entries, the plotting of which 'must cost 

 much in time and in money. Indeed,' it may be a 

 matter for consideration whether, at this preliminary 

 stage of the inquin*-, they might not be dispensed with, 

 without much loss, seeing that the "chronological 

 summan." " under each species supplies all, arid more 

 than, they do. 



The time is yet far distant when a digest of the valu- 

 able records in this report arid its three predecessors 

 can be attempted. It. does seem, however, that, unless 

 simultaneous observations can be taken over a far 

 wider area than a portion of the British Isles, the true 

 solution of the intricate and baffling problem of migra- 

 tion will not be greatly advanced. Besides ascertaining 

 the flight-lines of the birds arriving in or departing 

 from England and Wales,' the state of the weather and 

 the abundance or scarcity of food at these periods, we 

 want to discover whence the individual birds that 

 reach us in spring started; where those that nest 

 within our shores in autumn actually spend our 

 winter; why they adopt the particular routes they do ; 

 why they hasten to "change their skies " now to the 

 north, now to the south; if the same individuals and 

 their young invariably follow the same route in going 

 and returning; and if they and their young drop out 

 of the migrating flock ever\- year at the same places 

 in order to "build and brood in their old haunts." 

 The pressing need in the migration inquiry- is for the 

 systematic marking in ver\- large numbers, not onlv 

 of nestlings, but of old birds, in this country and on 

 the Continent of Europe, during both the summer and 

 the winter visitation, but also, which is equallv impor- 

 tant, of those that spend our winter in southern lati- 

 tudes, and at various halting places of the ranges of 

 the species from furthest north to furthest south, in 

 the -Asiatic, Euro-.African, and the American con- 

 tinents. 



If the mark attached to the birds were a small 

 facetted ring of aluminium, a light metal which 

 long retains its brilliancy, it would often attract the 

 eye by flashing in the sun, and thereby many birds 

 would be detected as marked individuals bv interested 

 or chance obser\-ers on the look out for them, in 

 districts especially where such labelling was known 

 to have taken place. The birds could then be fol- 

 lowed up, temporarily captured for their mark to be 

 recorded, and then liberated, and the record thereafter 

 promptly published. Until some such united action 

 and extended system for identifying the movements 



