AND OF THE PHYSICAL SCIENCES. 



127 



still linger with us in spare quantities. In England the Madrepores arc reduced to 

 two or three species, of rare occurrence and diminutive size ; the Gorgoniat are also 

 comparatively small ; and the Gorgonia fabellvm of the tropics has been two or three 

 times found on the Cornish and Leith shores. Instances of this kind might readily 

 be multiplied. 



It appears, from the foregoing remarks, that however desirable it might be, in all 

 inquiries hke the present, to determine general or primary laws, and that however 

 obvious it may be that such determinations should be the principal aim of naturalists, 

 yet the subject we are inquiring into will scarcely allow us to proceed farther than 

 the discovery of secondary influences. But since these are liable to have an undue 

 importance ascribed to them, and to be viewed as primary laws, it would be right, aa 

 far as possible, to ascertain their absolute weight, and to see how far they modify 

 those more general influences. 



It remains to be observed, that there are a certain number of facts in the Geogra- 

 phy of Animals which do not appear to come under any law ; nor are they explain 

 able by, or referable to, any cause of which we have knowledge. No species of ani- 

 mal is cosmopolitan, but the extent of geographic range of species varies very largely. 

 The greatness of this extent, however, is, except in a comparatively few cases, so or- 

 dered that there are certain divisions of the globe inhabited by races of animals 

 peculiar to them, these races defining, as it were, by their limits, the zoological 

 divisions of the earth. Thus, with a few exceptions (not considering those cases in 

 the northern parts, where the two continents join or approximate), the Fauna of 

 America is peculiar to it; and the same may be said of Australia, with the difference 

 only of still fewer exceptions being present. Now, besides the exceptions to this 

 rule of exclusive Faunas, the ranges of animals within their zoological divisions is 

 frequently very extensive ; whilst, on the other hand, the limits of very many are 

 extremely circumscribed, sometimes a small spot of land, or a single river, being the 

 extent of the habitat ; in all of which cases, no clue to the cause of such peculiarities 

 can be discovered. Indeed, unless we at once confess that animals occupy stations 

 on the earth assigned to them by the will of the Creator, and determined only by a 

 Providence and an Omnipotence perfectly inscrutable by us, we must be content to 

 believe that animal distribution depends on circumstances conni^cted with the con- 

 stitution of the species, of the nature of which we are ignorant, and likely to continue 

 so. It is not enough to point out instances of evident adaptation of animals to the 

 circumstances which surround them, or to show that their peculiar food is found 

 around them ; for it might easily be demonstrated, that, in numerous cases, the same 

 circumstances and the same food abound where the animals never come, and where, 

 if brought by man, they readily become naturalized. It is not enough to say, that, 

 in the instances where no adaptation is manifest, it nevertheless must exist, because 

 we see that these animals are invariably found in one particular kind of situation ; for, 

 although some do certainly confine themselves as thus stated, yet they are frequently 

 peculiar to one region or spot, and denied to others equally suited to their existence ; 

 besides which, there are kinds that, in seeming opposition to the whole analogy of 

 zoological science, occupy a range of country or of abode, including opposite kinds of 

 circumstances and situations, and these instances occurring too in the same tribe or 

 family, where, as above stated, adaptation was in some species proved by the uniform 

 character of the abode. 



With respect to migration also, the causes are not always obvious, for birds of 

 precisely similar endowments and character observe different habits, some migrating, 

 and some being fixed; whilst at times the migrating species will for the winter remain 

 with us, and seem to live as well as our common residents, so that the reason of mi- 

 gration is not always clear. The Llama and Vicugna, and the Sapajous, are peculiar 

 to America ; the Ornithorhynehus, Kangaroo, and Wombat, to New Holland. The 

 Jay inhabits equally almost every country of Europe, and the immediately adjoining 

 Asiatic countries, but extends no farther. The Barn Owl inhabits Europe, America, 

 and part of Asia, and to rny own knowledge some of the South Sea Islands. The 

 Peregrine Falcon inhabits Europe, America, and Australia. The Blue Jay is con- 

 fined to North America, the Leptocephalus morisii to the southern shores of England ; 

 and the Physa alba to the River Towyn of North Wales. The Sapajous, or pre- 

 hensile-tailed Monkeys, are certainly well adapted to the forests of America ; but are 

 they less suited to the forests of other countries ? The Nightingale certainly finds 

 its peculiar insect food in those countries, and counties in England, to which it now 

 resorts, the climate also being congenial to its feelings and habits ; yet though it is 

 found in Sweden and Germany, it is absent from Scotland and Northumberland, and 

 though it is found in the middle and some southern counties of England, it is not seen 

 in Devon or Cornwall. The Great Bustard is found enjoying a distribution lalitudm- 

 ally, whereas the same climate, situation, and food, could be obtained to the north and 

 south of this zone. The Achatina acicula, though found in some limestone districts 

 of England, has never been seen in the south of Devon, where lime abounds. The 

 Swallow never migrates to America or Chma, though the food and climate there 

 would suit its constitution. The Hedge Warbler is stationary, while the Blackcap 

 migrates. Lastly, the Willow Wren, which ordinarily migrates, will yet at times re- 

 main with us through the winter. 



The first of those secondary causes or influences, ranking as laws of geographic dis- 

 tribution of animals, which we shall mention, is Climate^ a term which includes a con- 

 sideration of temperature, of seasons, of winds usually prevalent, of the dryness or 

 humidity of the air, of rains, drought, continued cold or heat, &c. It deserves notice 

 that the presence of mountains, rivers, seas, barren spots, the quality of soil, the de- 

 gree of cultivation, and the clearness or cloudiness of the sky, have all some influence 

 in forming the climate, and in consequence the Fauna of a country. Secondary laws 

 seem to act and re-act largely on each other, so that no one of them appears to have 

 a separate or unmixed influence on animal distribution. The influence of climate on the 

 distribution of animals may at once be seen by considering the vast increase of living 

 beings as we approach the equatorial regions from the poles ; but then it must be 

 dearly understood, that this effect of climate, or rather of heat, is observed only in a 

 very general way, and that, owing to a great variety of causes, some quite incompre- 

 hensible, others connected with food, situation, &c. The interruptions of this rule of 

 increase are both numerous and important ; still, on the whole, heat may be considered 



one of the secondary causes that influence the geography of animals. The alternations 

 of the seasons, which, besides bringing an alteration of temperature, induce consider- 

 able difl'erence on the food of animals, have a decided influence on their situations, 

 causing a variety of movements termed Migrations. These changes of place are more 

 immediately dependent on temperature and the state of the atmosphere, than on food, 

 or other causes. Winds frequently afl'ect the Fauna of a country, by driving aquatic 

 animals to land, or by putting migrating animals from their destined courses. The 

 state of the atmosphere as regards dryness or humidity, together ivith a continuance 

 of rains or drought, will affect the general nature of the chmate, and thereby the vege- 

 table produce and animals of the country in which such conditions occur. Unusually 

 hot or fine summers are most likely the causes of our receiving certain birds from the 

 southern parts of Europe at that season. Long continuance of vvet and cold at the 

 time of the autumnal migration, will influence the period of departure of perhaps all 

 our summer visitants. 



Geographical situation, relations, and arrangement of a country, have considerable 

 power over the extent and nature of a Fauna. The adjacency of an ocean, or large 

 river in connexion with the sea, implies of course the presence of marine productions; 

 the intersection of a country by smaller rivers and inland waters, will afford fluviatile 

 and lacustrine animals ; mountains and hills are the resorts of a variety of creatures ; 

 heaths and uncultivated spots have their pecuhar animals ; cultivated land, by originat- 

 ing a large proportion and variety of plants and trees, invite thither a great variety 

 of passerine and other birds, either in search of insects in connexion with the vegeta- 

 tion, or for the purpose of feeding on the various seeds ; together with the passerine 

 birds are found the Climbers, they being insectivorous ; and, lastly, certain of the 

 Hawks, or other predatory birds allured thither by the presence of smaller species. 



Such is the usual ornithology of many of our wooded districts in Devon, and not- 

 withstanding that we owe much to our hills and heaths, perhaps our geographical po- 

 sition and our relations to other countries, and, above all, the extent of our woods 

 and cultivated ground, may be considered as more generally influimtial in determining 

 our species of birds than any other secondary cause. Certainly Devon and Cornwall 

 are two of the mildest counties in England, and in conformity with that character, 

 the Stone Curlew has been known, according to Montagu, to remain all winter with 

 us at the Start, the most southern point of land in England, except the Lizard 

 in Cornwall. So also the Chiff-chaff" was observed by the same eminent naturalist 

 to stay the winter with us near his house at Kingsbridge. 



Storms and other phenomena of weather referable to the head Climate are, as 

 above said, and as will ih the sequel be illuitrated, of considerable consequence 

 in forming and influencing a Fauna ; but Climate is very much dependent on situation, 

 arrangement, and other local circumstances of a country, especially adjacency of sea, 

 which renders the temperature of all countries bordering on it mild and agreeable, pro- 

 vided the prevalent winds are in a direction from it. If Devon were not situated in 

 connexion with the sea, of course no mildness of climate, or storms, or phenomena of 

 that kind, could confer on us those marine products so conspicuous in our Fauna; and 

 if our situation were not at the southern limits of the island, and opposite to the 

 southern states of Europe, we should necessarily have none of those animals which by 

 accident, or the invitations of unusually fine weather, cross over to experience the 

 gentle warmth of our summer, or else are driven by the violence of equinoctial storms 

 on our coasts ; or, lastly, in the case of autumnal migrants, are enticed to stay the 

 winter with us by reason of our southernmost locality, together with agreeably genial 

 warmth. 



The Flying-fish has occurred to the north of us, in the Bristol Channel, possibly 

 under the influence of equinoctial gales ; yet our situation must be taken into account 

 rather than this phenomenon of our climate. The Hippocampus vulgaris and Ecfdneis 

 litmora have both been captured on our shores, yet situation, equally with, or proba- 

 bly more than climate, should be regarded as the cause. Many of our birds are in- 

 fluenced in their visits hither, and in their stay with us in winter, as well as in many 

 peculiarities of movements exhibited by them, by our climate ; but the abundance of 

 wood and shelter, and the diversification of the surface of cur country, will alone sup- 

 ply some explanation of the vast number of terrestrial birds found with us. Conse- 

 quently, not only must we be compelled on most occasions to consider these two causes 

 of distribution, climate and geographic position, with the other physical conditions of a 

 country, in connexion, but to reflect that the latter influence is of the two the more 

 powerful and extensive in operation. 



If it were demanded of us to state the general nature and qualities of the climate of 

 South Devon, we should say it was characterized by equality of temperature and hu- 

 midity of atmosphere. Our summers are short, generally fervent, and attended by 

 long droughts ; our autumns are particularly rainy ; our winters stormy, and sometimes 

 very cold and lengthened; our springs chilly, unsettled, deceptive, and on the whole 

 characterized by frequent intervals of gentle warrnth of short continuance, between 

 the long-continued rains, the protracted blasts, and blighting winds, ordinarily pre- 

 valent. Vegetation having made seveial unavailing efforts in these intervals, and 

 having received frequent checks and blights, is at length permitted to put forth its 

 energies in May. Occasionally this month is with us unusually dry and fine, so as 

 to be productive of calamitous consequences both as regards the feeding of cattle, and 

 the crops of grass and corn ; for at this period vegetation makes its greatest efforts, 

 and requires a supply of moisture to proceed with, in defect of which the harvests are 

 rendered late and scanty, and cabbages and other garden produce are greatly injured. 

 All this happened to us last year. Occasionally also, and such was our lot in the pre- 

 sent year, May is uncommonly unpropitious, and vegetation makes no decided advances 

 till June. On 2-ith March, snow fell and lay three or four inches deep, and ice formed 

 in the estuary of the Yealm half an inch in thickness. On the 2d April, snow again . 

 fell ; on the 1 1th, a fresh deposit took place, and in some spots remained two weeks. 

 There were no leaves on the trees till after the first week in May ! In the end of 

 March, frosts even entered our hot-houses, and destroyed the young grapes. 



According to my remarks, the arrival of spring birds of passage is deferred in ac- 

 cordance with the weather experienced in that season. They arrived late in the pre- 

 sent year, or, at all events, were not seen or heard till after their usual periods. It 

 is much easier to state facts than to assign reasons for facts; and so in the present 



