Each year there are two periods of migration, spring migration occurred February to May when birds headed to their breeding grounds from where they over wintered and then there is the autumn migration which will be taking place by the time you read this article.
Bird migration, in general, is amazing but very complicated and not a lot is known about it however, for those of you who watched Springwatch, some information is being found out about migration from bird ringing – safely trapping birds, attaching a metal ring on their leg, recording the unique numbers and/or letters then releasing the bird. If and when it gets retrapped , the number could tell that person where and when it was rung – hopefully many miles away. More modern technology such as small satellite tracking devices are now being attached to birds such as cuckoos and arctic terns. It was known that these two birds, in particular, migrated to Africa but it was how far and what path they chose which was not known until these GPS tracking devices tracked the exact track the bird flew.
More information can be found on the British Trust for Ornithology who collate all of the information from bird ringers and keep a database.
If you do find a dead bird with a ring on it you can report it to the BTO, give them the numbers and/or letters, they will send you details of where that bird was rung and they will update the information of where and possibly how the bird died, all very vital information.
Although the two migrations involve birds moving from one site to another, in the spring birds are rushing to get the best breeding ground and the best partner and so they travel as fast as possible to get there. Yes, they will rest at watering holes to feed and drink but they need to get to the site as soon as possible. The Autumn migration is a little different in that the breeding is done and the majority of birds will be travelling back to where they overwinter but not in such a hurry and may hang around at watering holes and rest points a little longer, allowing us twitchers to see them better. This time of year different weather conditions appear over the Atlantic and the continent and these conditions can force rare birds to end up in the UK and also aid/restrict general migration. The parents also have their young in tow, still teaching them to hunt and feed before the flight to their wintering grounds.
By the time you have read this article cuckoos and swifts will have already left the UK and are heading to Africa via mainland Europe, warblers – such as common whitethroat and sedge warbler are preparing to go and house martins and swallows are feeding up for the long flight. The hedgerows along the canals and rivers will start to empty with the warblers going but soon they will start to be replaced by fieldfares and redwings, coming in from Scandanavia, and also more common species – blackbird, robin, bullfinch – will all be swelled in numbers by birds coming from abroad to winter in the “warm” UK.
There is also an internal migration, birds such as meadow pipits have bred on moorlands but will seek lower ground to winter. Golden plovers, curlew and oystercatchers breed inland on moors and gravel pits but will migrate to the coast to winter with thousands of their own species.
Look for birds in the trees and hedgerows. Sounds obvious but birds are moving through and they still need to eat, searching for insects and seeds as they go. Bird numbers will be multiplied by the juveniles which also have to migrate and they will be wanting as much food as possible to build their strength and stamina for, in some cases, a very long flight. Juvenile redstarts, whinchats and spotted flycatchers can turn up almost anywhere.
One family member of birds easy to see during migration are waders. These are birds of varying size that generally tend to favour the muddy estuaries during the winter months however whilst on passage (the movement during migration) birds can end up anywhere were there are mud flats, even canals and rivers. Green sandpipers are generally the first birds to return, a small browny green wader with a striking sharp blast for a call, these can easily occur on rivers and canal banks. So can common sandpiper, very similar to green sandpipers but these birds bob as they walk around hunting food. Redshanks are also easily seen on rivers and canals and are obvious birds with their bright red legs.
The Canal & River Trust has top team of committed experts and enthusiasts, who help to protect our waterway environment and improve it for both people and nature. Follow this blog to find out more about the hugely varied work they carry out.See more blogs from The environment team