Birds, 139 



disappear from the throat in both sexes, and the dorsal plumage be- 

 comes of a lighter colour in each ; the back of the male assuming the 

 grey of the female during the breeding season, while that of the fe- 

 male and the young of the year in both sexes changes to a very light 

 grey. Indeed, between the two latter, there is no external difference 

 of appearance. 



About the middle of August the pied wagtails commence their re- 

 turn towards the sea-coast, and now first appear to be gregarious in 

 their habits. At this season I have noticed them in considerable 

 numbers on village commons, and similar localities in the interior of 

 the county, where they remain but a few days, and then proceed to 

 the south. At the latter end of the month, or the beginning of Sep- 

 tember, they may be seen near the sea, in flocks of from thirty to forty, 

 flying invariably from west to east, parallel with the shore, and fol- 

 lowing each other in constant succession. These flights continue 

 from daylight until about ten o'clock in the forenoon ; and it is a 

 remarkable fact, that so steadily do they pursue this course, and so 

 pertinacious are they in adhering to it, that even a shot, fired at an 

 advancing party, and the death of more than one individual, cannot 

 induce the remainder to fly in a different direction ; for after opening 

 to the right and left, their ranks again close, and the progress towards 

 the east is resumed as before. 



I have observed that their proximity to the shore, during this tran- 

 sit from west to east, seems to depend in some degree upon the cha- 

 racter and extent of the country intervening between the downs and 

 the sea. For instance, in the more western parts of the county, be- 

 tween Chichester and Worthing, where a flat, maritime district, of 

 considerable extent, and in a high state of cultivation, lies between 

 the hills and the sea, the flocks appear to be less numerous, or rather 

 more scattered, and occur at greater distances from the coast than in 

 the neighbourhood of Brighton, where the downs approach closely to 

 the shore, and where the flocks appear to become more concentrated. 

 I am acquainted with a good practical observer, who informs me 

 that in the neighbourhood of Brighton, he has seen upwards of a thou- 

 sand pass in a single morning. The same person has witnessed, as 

 well as myself, the arrival of these birds from the continent in March, 

 on the open coast near Hove, between Brighton and Shoreham. 



I think there can be but little doubt that these flocks, the greatest 

 proportion of which consists of the young birds of the year, at this 

 time but a few months old, in thus pursuing their course along the 

 shore in an easterly direction, are impelled by a wonderful instinct to 



