Across the region we have a fairly new coloniser to the rivers and reservoirs, and that is the‘goosander’.
This is a member of a group of birds called the ‘sawbills’ on account of their bills having serrated edges – ideal for catching and holding the slippery fish on which the goosander feeds. Like so many predatory birds the goosander declined with a mixture of water pollution and hence few fish to eat, DDT pesticide pollution that stopped the birds breeding, and then if that wasn’t enough, persecution by water bailiffs on rivers or lakes where fish did occur.
This heady mix of trouble meant goosanders were extinct in lowland England and indeed, as a teenage bird-watcher the first ones I saw were on the River Lune in Lancashire when I went as a student to Lancaster University.
The males are stunningly showy with pinkish-white belly and flanks, and a gorgeous, iridescent green head. They don’t generally show a ‘crest’, but leave that to the smaller cousin the red-breasted merganser; however, they can raise the head feathers to show-off to a rival male as I observed recently.
The dominant male stood almost upright and raised its dark green head-feathers whilst it opened its bill wide in a clear show of aggression to a rival.
The females lack the green head and the bright underside. They are mainly dull white and grey with a reddish brown head and a crest in the style of a punk haircut.
The juvenile birds are similar in size and plumage to the females and both groups are often referred to generically as ‘red-heads’; they are hard to tell apart.
Today, this is a species that has spread spectacularly and you can see them on many urban rivers, on reservoirs and on millponds. In winter, look out for flocks numbering into the tens or more on favoured loafing ponds. Of course not everyone is happy to see this bird back in town as they eat plenty of fish and so some, though not all, anglers are dismayed by their return.
Professor Ian D. Rotherham, of Sheffield Hallam University, researcher, writer and broadcaster on wildlife and environmental issues.