14 INTRODUCTION. 



Andalucian Quail. Generally speaking, it seems to me that 

 in the vernal migration the males are the first to arrive, as 

 with the Wheatears, Nightingales, Night-Herons, Bee-eaters ; 

 but this is a theory which requires more confirmation. Some 

 species, as the Neophron and most of the Raptores, pass in 

 pairs. 



Most of the land-birds pass by day, usually crossing the 

 Straits in the morning. The waders are, as a rule, not seen on 

 passage ; so it may be concluded they pass by night, although 

 occasionally Peewits, Golden Plover, Terns, and Gulls have been 

 noticed passing by day. 



The autumnal or return migration is less conspicuous than 

 the vernal: and whether the passage is performed by night, 

 or whether birds return by some other route, or whether they 

 pass straight on, not lingering by the way as in spring, is an 

 open question ; but during the autumn months passed at 

 Gibraltar I failed to notice the passage as in spring, though 

 more than once during the month of August myself and others 

 distinctly heard Bee-eaters passing south at night, and so 

 conclude other birds may do the same. 



We have (vide Andersson's ' Birds of Damara Land,' pp. 18- 

 21) an account of the swarms of Hawks which appear there at 

 the time they are absent from Europe and North Africa ; so it 

 may be reasonably inferred with regard to one species, Milvus 

 migrans (the Black Kite), that some of the vast numbers which 

 pass the Straits of Gibraltar retire in autumn through the tropics 

 to South Africa. 



The best site for watching the departure of the vernal 

 migration is at Tangier, where just outside the town the well- 

 known plain called the " Mashan," a high piece of ground 

 that in England would be called a common, seems to be the 

 starting-point of half the small birds that visit Europe. 



Both the vernal and autumnal migrations are generally 

 executed during an easterly wind, or Levanter : at one time I 



