HARD WICKE 'S SCIENCE ■ G OSS IF. 



247 



THE PAIRING INSTINCT OF BIRDS. 



By Charles Dixon. 



'"I'^HIS subject has always been one of much 

 -L dispute among;st naturalists, and indeed one 

 of a very pei-plexing nature. I have found it to 

 be a subject which few writers on ornithology treat 

 with a proper amount of care, while others refrain 

 entirely from introducing it into their works. I 

 consider it to be one of the most important traits in 

 the character of the feathered tribes — an amovmt of 

 instinct given alike to the lordly eagle and the dimi- 

 nutive wren ; I cannot believe, with some persons, 

 that instinct is only a certain power inherited from 

 the parent birds. Of its manifold uses I am not 

 going to treat, they being at variance with the present 

 subject. But if birds inherited this power from their 

 parents, as some assert, they would all employ these 

 powers in the same manner peculiar to their species, 

 as their kind have done before them for ages ; but 

 witness the many different fonns of instinct dis- 

 played by birds which are only applicable to the 

 surrounding circumstances, powers which perhaps 

 no other birds of their race have had to exert 

 before. 



Birds may be divided into three classes; viz., 

 firstly, those birds which, having once paired, remain 

 together for life ; secondly, birds which pair annually ; 

 and, thirdly, birds which never pair, but are poly- 

 gamous. I will briefly glance at these three divisions, 

 and give the opinions I have arrived at in a matter to 

 which I have paid special attention. 



"We will take firstly those birds which pair for life. 

 Swallows are an excellent type of this class, returning 

 annually to their old 7iesfiHg-siies, for the same 

 purpose as previously. The Martin returns to its old 

 nest. But to some this may appear incredulous, 

 knowing that these birds perform long migrations, 

 and may get separated while upon them. Do these 

 birds get finally sepai-ated when in large companies 

 they are searching the air for their food ? or do Rooks, 

 Starlings, and Jackdaws fail to remember the position 

 of their nests ? The same instinct which informs the 

 Swallows when to leave Africa in like manner urges 

 them onwards to their old nests ; and again the same 

 pair of birds will perform the duties of incubation. 

 We all know that the same nesting-site will be yearly 

 tenanted by its former owners, provided they are 

 left unmolested. This must be by the same pair of 

 birds, for what ornithologist has ever, in the course 

 of his observations, seen swallows piying about into 

 barns and outbuildings in search of some old nest, 

 which will save them the labour of constructing one 

 themselves ? The time would be so taken up in this 

 search, that no brood would be reared. Young birds 

 pair most likely before their migration to us, and 

 search out nesting-sites upon their arrival in this 

 country. 



Again, the Rook is another bird which I believe 

 pairs for life. At the commencement of the breeding 

 season rooks (unmolested by the other members of 

 the rookery) return to their old nests, and commence 

 doing the necessary repairs required for the comfort 

 of their future brood ; while others, whose nests have 

 been destroyed, diligently set to work to reconstruct 

 them, in company with many of the last year's 

 brood which have paired some time during the 

 previous six months. Can any ornithologist inform 

 me of any combat he has been witness to for the 

 choice of the nests which have withstood the storms 

 of winter? A few pairs of rooks will sometimes 

 desert the general rookery and build their nests in 

 neighbouring trees, returning to them yearly. 



Ravens, Magpies, Jackdaws, Starlings, House 

 Sparrows, several of the Falconidm and ParidcE, 

 have all been known to return to their nests of 

 the previous season. I have known the Robin and 

 the Wren return to their old sites (but not to the old 

 nests) for several years. From these instances I would 

 infer that all birds which return t'o their old nests or 

 nesting-sites for the same purpose every season pair 

 for life. 



In the second place, those birds which pair 

 annually ; the birds which fonn this division are the 

 most numerous of any. We have many instances of 

 this class : as a good type, we will take the Willow 

 Warbler. When these birds first arrive in this 

 country they ai'e never in pairs. But observe them a 

 few weeks later ; they have all found a mate, and are 

 employed in domestic duties. It is the nature of 

 these birds to make fresh nests every season, and 

 never in the same position or locality. When once 

 these birds have left their nests and the young can 

 forage for themselves, I firmly believe all connection 

 between the two birds ceases ; the nests are aban- 

 doned, never to be returned to, and the birds roam 

 about searching for food, very often solitary, until 

 the time of migi-ation arrives. Several of the Thrushes 

 are for the most part solitaiy in their habits, except 

 in the breeding season, while others roam about in 

 flocks, very often the males or females being predo- 

 minant, but as spring arrives, separating into pairs 

 for incubation ; after which the same routine is again 

 repeated. The Chaffinch is the same — in flocks 

 during the winter, the sexes not at all social ; but as 

 the breeding season approaches they are again seen 

 in pairs for the propagation of their species. The 

 Pigeons, Partridges, Snipes, Plovers, and Rails, all 

 pair annually. In the same manner the Buntings, 

 Larks, many of the Finches, Warblers, all pair in 

 their due season. 



All these birds' nests, after once serving their 

 purpose, are abandoned for ever : a walk round the 

 leafless hedges will confirm this. Will the frail little 

 Whitethroat use yon abode again ? or the Sandpiper 

 return to the cavity which once contained her eggs ? 

 These birds pair annually, and of course select each 



