NA TURE 



;29 



THURSDAY, JANUARY 12, 191 1. 



MlGRklORY BIRDS. 



The Book of Migratory Birds, met with on Holy 

 Island and the Northumbrian Coast, to which is 

 added descriptive Accounts of Wild Fowling on the 

 Mud Flats, with Notes on the General Natural 

 History of this District. By W. Halliday. Pp. 

 258. (London : J. Ouseley, Ltd., n.d.) Price 55. 

 net. 



THE obtrusive title of a work should, we think, be 

 more closely descriptive of its contents than that 

 of the volume now before us. "The Book of Migra- 

 tor}' Birds " — the title conspicuously appearing on its 

 cover — excites hopes in the ornithologist of a com- 

 prehensive contribution to a branch of his science of 

 unquestioned interest. His momentary disappoint- 

 ment, on discovering from the continuation of the title 

 inside, the restriction of its scope to the Northumbrian 

 coast, may perhaps be relieved on his recalling the 

 fact that the district, with its offshore islands and 

 lighthouses, forms a migration-observator}' from 

 which a keen and persistent watcher might be ex- 

 pected to make valuable contributions to the 

 question. His annoyance, however, will be acute 

 when, on dipping into its pages, he finds the volume 

 to be only a melange of articles, strung together in 

 the most casual way, and evidently originally con- 

 tributed to some newspaper or journal in which either 

 science was not a strong point or the editorial super- 



ision was far from exacting. 



The first part consists of a score of essays, not one 

 without need of vigorous revision by a competent 

 zoologist, while the second describes a certain number 

 of the species of the Northumbrian coast individually ; 

 the book, however, makes no serious contribution to 

 migration data, nor adds anything new to the 

 histor\- of the species observed. The first thirty-seven 

 pages are alone specially devoted to the bird-life of 

 Lindisfarne and the Fame islands, but the short and 

 desultor}- notes on the species mentioned will hardly 

 pay the reader for his time. The succeeding three 



-says deal with " wild-fowling " as far removed from 

 Holy Island as North Kent; with "a few comments 

 on sport," and "how I became a naturalist," this last 

 filling eight pages, of which five contributed by 

 another pen, have no connection in the world with 

 the autobiography. With the following two, on "bird 

 migration " and " bird migration from America to 

 Europe," hope rises that at last some new ideas on 

 the subject giving its dominating title to the 

 book are to be disclosed. We are not disappointed 

 by the author. 



" Whatever theory is advanced [on this absorbingly 

 interesting question] the idea," writes Mr. Halliday, 

 "baffles the most devoted student of natural history. 

 Yet the query as to the causes of the northern or 

 spring exodus has prompted me to make an effort to 

 explain . . . those laws. . . . Almost without excep- 

 tion . . scientists are agreed that previous to 



NO. 2150, VOL. 85] 



tne period termed the Glacial or ice age, climates 

 were non-zonal — that is, that they were ot the same 

 general temperature everywhere from pole to pole. 

 rirst, that there was an epoch of torrid heat followed 

 by one of tropical heat, and succeeded by one of tem- 

 perate heat, which gradually passed into one of exces- 

 sive cold, during which period the higher lands were 

 snow-covered. . . . Since this age the climates have 

 become zonal — a condition which seems to us most 

 natural, because man remembers naught to the oon- 

 trary.[!] The geological record shows us, however, 

 that everywhere from pole to pole the same life existed 

 during all the periods before the latter part of the 

 temperate Tertiary epoch. Aside from these differ- 

 ences of temperature resulting from elevation , . . 

 there were in the nature of things few reasons for 

 migrations of either fauna or flora . . . when finally 

 the gradual transition from earth-heat control to sun- 

 heat control had taken place, and the Ice age began, 

 these wanderings to and fro become systematic and 

 periodical. The stronger and more, active individuals 

 pushed further on than their fellows, as they climbed 

 up further on mountain sides, thereby forming a class 

 apart. They mated and founded new varieties. . . . 

 So here we have, in its earliest and simplest form, the 

 origin of the migratory movements of animals which 

 have developed to such an extent in this day under 

 the present zonal distribution of climates. Thus we 

 mav conclude," adds the author, " that, beginning with 

 the first modifications of climate, perhaps at the com- 

 mencement of the Pleistocene era, the various forms 

 of life being suited to a uniform environment sought 

 in their wanderings to and fro, the continuance of 

 these conditions." 



So here at last we have the final word on phenomena 

 which have puzzled generations of ornithologists and 

 others ! 



After such epoch-making discourses as these, a dozen 

 other essays — evident reprints — follow on a variety 

 of matters unconnected with the subject of the book, 

 yet containing many entertaining observations not to 

 be found in more recent ornithological histories I 



The second part of the book describes individually 

 forty-two species only out of the ninety listed on p. 22 

 as the more or less complete avifauna of Holy Island 

 and region. They are not arranged in any classifica- 

 toiry order, nor, in many cases, do they appear under 

 the generic and specific names which are usually given 

 them bv the rules of nomenclature. Fuller and more 

 accurate accounts of these species are to be found in a 

 score of well-known histories of British birds. We are 

 staggered to find in this catalogue of Northumbrian 

 birds the names of the cassowary and the ostrich, 

 sandwiched between the quail and the merlin. We 

 live and learn, however! Of the two final essays, 

 both of which appear under the headline of " The Book 

 of Migratory Birds," the one on North Sea seals may 

 be legitimately included in a work on Northumbrian 

 natural history'; but it is a far cry from longshoring 

 on Lindisfarne to "seal-hunting in Greenland," which 

 is the title of the other. The author, however, makes 

 his own apologies in these words : — 



" If the able and experienced chroniclers of the 

 migrants in the past have written craving the indul- 

 gence of the reader, I feel I am infinitely more in need 

 of such indulgence, and as a man is but mortal . . . 

 his best work is oft-times a sorry attempt." 



M 



