BLACK TERNS were seen over lakes and reservoirs in many parts of Britain yesterday. This autumn there has been a noticeable passage of these birds across our country on their way to West Africa from the marshes of northern Europe.
They belong to a group of terns that have black bodies in the summer, called marsh terns. Some of these passing migrants are still very dark-plumaged, though in winter only their head will remain black. They look like bird shadows as they flit lazily over the water, or drop down to take insects from the surface. Here they are mainly seen in ones and twos, but on Mediterranean and African estuaries they gather in enormous flocks.
Another scarce migrant that was spotted on several reservoirs yesterday is the red-necked grebe. In summer it has a handsome chestnut-red neck and breast, but it is very similar to our great crested grebe when both species are in their black-and-white winter plumage. However, the red-necked grebe’s black cap comes right down to its eyes, while the great crested grebe’s cap sits on the top of its head.
DJM