I was wandering a new housing estate near Fleet. It was like our new Napsbury estate, except it was on a slight slope. A stream flowed through the estate, and the developers had built a dam across it to form a lake, and had laid out paths and ornamental bushes around the lake. It was interesting to see how nature was colonising the lake. Around the lake edge were bull rushes.These will need watching! When they die, they sink to the bottom, and new rushes grow atop them. If nothing is done, this could lead to the lake vanishing. I was amazed at the number of birds on the lake.
The commonest were black headed gulls. You see them round our village, particularly following ploughs, to eat the grubs that are turned up. In spring, when they breed, most black headed gulls have a dark brown mantle over their head - and the rest of the year this is replaced by a grey dot behind each eye. Trouble is - whenever you see a flock of black headed gulls, there is always at least one in breeding plumage!
The next commonest species were mallard. The males have glossy green heads, with a white collar and chestnut coloured bib. Both male and female have iridescent blue wing tips, but the female is always varying shades of brown, so they cannot be seen by predators as they sit on their nests. There were a couple of swans on the lake - a British species, and a couple of Canada Geese. These are definitely not a British species, but are descended from some geese which escaped from Woburn Park over 400 years ago. Whenever I see a settled flock of birds, I always look carefully at them in case there are any birds that should not have been there. Remember, even rare birds will join a flock of another species, because they are safer: if one bird sees a predator, it will raise the alarm, and in a large flock, there will always be two or three birds on the look out. I saw a pair of birds I had never seen before. They were a pair of sandcoloured ducks. Both had the upper parts of their bodies darker brown, and both had green feathers on their wing tips. However, the larger of the two had a dark brown tear shaped spot around its eyes. When I got home, I searched through several books to discover what it was I had seen. The birds were Egyptian geese. This was a bad name, as they looked like ducks, and rather than living in Egypt, came from northern Ethiopia. The question is - how had this pair of birds arrived in England? It's unlikely they'd flown from Ethiopia. More likely they'd escaped from a wild bird park or zoo. And what of their future? They'll probably mate and produce young, and when their young are sufficiently old, they'll leave their parents and seek a home on another lake. They might well meet others of the same species and breed with them.
Ornithologists regularly conduct surveys of bird species in the UK, and they reckon that each summer, in Britain, there are between 100 and 1000 pairs of Egyptian geese, and most of them are resident in Norfolk.
Another question is - should we be worried when alien species come here and flourish? Possibly not. Any foreign duck living here will be competing with already established native species for the same food, and similar nesting sites, so they will be unlikely to displace any local species. Remember, the collared dove, which is originally from Siberia, was first found breeding in East Anglia in 1953. They have now spread all over the UK, they are not all that common, but you see them from time to time in our village, and no other species has suffered as a result. The Canada goose is a bit different. They are rather larger than any British species of goose, eat similar food and seek similar nesting sites. Because of their vigour, and aggression, they have ousted many British species of goose, so that today, whenever you visit a British lake, you are sure to see Canada geese, but rarely any other species. Perhaps we should have done something a couple of hundred years ago! In general,when an alien species arrives, unless it is likely to be a pest on commercial farming, or a vector for a particular disease, it is probably best to do nothing. What do you think!
Robin Cooper