xii PREFACE. 



the neighbourhood of Belfast. The differences between 

 these supposed species are 



" 1st. In size ; but a female specimen of L. ridibundus, 

 with black hood, bill and legs arterial blood-red, was exhi- 

 bited, agreeing in the size of body, tarsi, &c. with L. 

 capistratus. 



" 2nd. The colour of the tarsi and toes attributed to 

 L. capistratus, and as distinguishing it from L. ridibundus, 

 is a mere transition shade, through which all individuals 

 of the latter pass before the arterial blood-red hue is at- 

 tained. 



" 3rd. The disposition of black or brown on the head, its 

 taking the form of a mask, as in L. capistratus, or as a 

 hood, as in L. ridibundus, is either transitional or acci- 

 dental,* and the shade of colour commonly varies from 

 the ' brocoli-brown ' of the former to the deeper tint of the 

 ordinary L. ridibundus. 



" A specimen of the L. capistratus , purchased at the 

 sale of Bullock's collection by Dr. Leach, and believed to 

 have been one of the first birds seen by Temminck, to 

 which he gave this name, is now in the British Museum. 

 By the kindness of Mr. George R. Gray, I made a critical 

 comparison of this bird with the specimen now exhibited, 

 and, excepting in the smaller size of the toes and webs of 

 feet, there was no difference between it and some of them ; 

 and from the adult female, L. ridibundus, in full summer 

 plumage it differed in the most trivial manner only. 



* I have known it to be both transitional and accidental, i.e. for birds to exhibit 

 the mask the first summer of their attaining adult plumage, and others the hood 

 in their first assumption of the black hood." 



