416 THE BIRDS OF HELIGOLAND 



the afternoon, to disappear in the course of it. Like many other 

 species, they travel only by daylight, for they are never seen at 

 the lantern of the lighthouse. Their time of migration is pretty 

 nearly the same as that of the Great Titmice; but they neither 

 appear quite as early in the spring, nor do they depart quite as 

 late in autumn, as the former species. 



The Blue Titmouse is confined exclusively to Europe. In the 

 north it advances beyond 60 N. in exceptional cases only, and in 

 the south hardly ever passes across the Mediterranean, not even in 

 winter. 



216. Marsh Titmouse [SUMPFMEISE]. 

 PARUS PALUSTRIS, Linn. 



Parus palustris. Naumann, iv. 50. 



Marsh Tit. Dresser, iii. 99. 



Mesange nonnette. Temminck, Manuel, i. 291, iii. 212. 



This little bird, with its silky, glossy black crown, was caught 

 here once many years ago, but has not been seen again since. Its total 

 absence from this island is surprising in the highest degree, inas- 

 much as the bird is known to nest as far north as central Scandi- 

 navia, is resident also in Denmark, and occurs as a common 

 breeding species in Sleswick-Holstein, and on the North Sea 

 islands, some few miles off' the coast of that province. According 

 to Rohweder, it is more numerous in that district during the 

 autumn migration than any other species of Titmouse. 



The Crested Titmouse has also been met with here only once, 

 while the Long-tailed and Bearded Titmice are likewise quite 

 exceptional occurrences ; the only way by which we can account for 

 the strange absence of all the members of this genus is that, with 

 the exception of the Great and Blue Titmice, all these species 

 travel during the autumn in a strictly southerly line of migration, so 

 that it is quite impossible to meet with them west of the meridian 

 line under which their nests are situated. 



217. Northern Marsh Titmouse [NORDISCHE MEISE]. 

 PARUS BOREALIS, De Selys-Longchamps. 



Parus borealis. Naumann, xiii. ; Blasius, Nachtrage, 147. 



Northern Marsh Titmouse. Dresser, iii. 107. 



This Titmouse has also only occurred here once, viz. on the 

 10th of November 1881. It is somewhat larger than the preceding 

 species ; the crown of the head is a dark slaty-brown, the back 



