 |
 |
 |
|
Home > Migration Watch > Results > Review of 2002 Review of 2002 Achievements 2002 was the first year of Migration Watch and we were delighted with the way the online survey took off. Just under 3000 birdwatchers registered as recorders and information from over 26,000 birdwatching visits were submitted to the website!
The number of birdwatching visits made varied greatly between observers, many managed one to five visits but the majority were able to submit records from more than five visits throughout the spring. Some observers were extremely active and submitted records from over 100 different birdwatching visits. David Harper from Sussex submitted an incredible 376 ‘lists’ to the website! Most recorders chose to send in records from a small number of sites, usually local patches or favourite weekend destinations; making regular visits to a small number of sites is the most valuable contribution to Migration Watch. At the other extreme, a few recorders submitted records from a large number of sites, one recorder managed to visit 84 sites during the spring – he certainly had an action-packed spring and saw lots of good birds! Weather and migration in 2002 Migrants have the amazing ability to know when to leave their wintering grounds in Africa, exactly what triggers them to start migrating north is still poorly understood: internal rhythms, poor conditions in the local habitat and day length may all play a part. Weather plays an important role during migration and affects their timing of arrival in Britain and Ireland. 2002 was rather a strange year; there was the usual trickle of Wheatears, Sand Martins and Swallows in early March and then a southerly airflow coming from Iberia during the last week of March brought some migrants to our shores exceptionally early such as Whinchat and Swift (which typically arrive in mid-April) aswell as some European species ‘over-shooting’ like Hoopoe, Alpine Swift and Black-eared Wheatear. Cool easterly and northeasterly winds coupled with ‘blocking’ depressions over Europe slowed migration down during early April and migrants were generally thin on the ground. By mid-April, high pressure and soaring temperatures across Britain and Ireland and much of Europe allowed many migrants to flood in. Looking at the maps and tables on the Migration Watch web pages shows an influx of many species during week 8 (14-20 April); the maps for Common Sandpiper, Cuckoo, Yellow Wagtail and Swallow are particularly striking. When illustrated graphically (Figure 1: Cuckoo and Common Sandpiper) the influx is also evident; the numbers of observations of Cuckoo during late March and early April were very low (as you might expect), then there is a large increase in observations in week 8, followed by a further increase in week 9. From late May onwards the number of observations of Cuckoo submitted to the website decreased, probably a result of fewer Cuckoos singing and therefore becoming less easy to detect. Figure 1: Number of observations by
week
Common Sandpiper
Week 9 (21-27 April) also saw many birds arrive; in particular there was a noticeable arrival of Wood Warblers, Whitethroats and Turtle Doves (Figure 2). Figure 2. Number of observations by
week
Whitethroat
Hop, skip or jump? The Migration Atlas has revealed much new information about the migration routes and destinations of migrant birds once they have departed Britain and Ireland; exactly how they enter the country in spring is still a bit of a mystery. In the first year of Migration Watch some interesting patterns have become apparent. Some species such as Chiffchaff and Sedge Warbler enter Britain in the south-east and then steadily ‘hop’ north, producing an effect of a wave moving north and westwards. The animated maps for Wheatear suggest that they enter Britain and Ireland via the south-west and ‘hop’ north and eastwards. Other species such as Common Sandpiper and Pied Flycatcher appear to largely ‘skip’ the south coast and ‘jump’ straight to their breeding grounds further north; the animated maps do not show a wave of birds moving north, rather the birds ‘appear’ directly in their breeding grounds suggesting that they overfly the south coast and fly directly to their final destination. Departing winter visitors As well as asking birdwatchers to record the arrival of spring migrants, we also asked for records of Fieldfare, Redwing and Brambling to track the departure of these species towards their breeding grounds in Scandinavia. The animated maps for these species were particularly brilliant and clearly showed a westward and northerly movement during early April and by week 9 (21-27 April) records were largely restricted to the eastern part of England and Scotland and over subsequent weeks eventually disappeared from the maps. Maps: Location of records by week for Redwing
Seasonal coverage The Migration Watch season ran from 1st March to 30th June. During the first few weeks the number of submissions increased quite rapidly as publicity for the survey peaked. The number of records submitted each week remained fairly constant until mid May, then the number of submissions dropped off (Figure 3). By mid May most birdwatchers will have recorded most of the summer migrants and the enthusiasm for ‘listing’ wanes. It will be important in future years of Migration Watch to encourage birdwatchers to record well into June to ensure that we have recorded the final destination of migrants. Figure 3: Number of visits per week for Britain and Ireland
By asking Migration Watch recorders to submit their sightings using lists we can look at the proportion of observers recording a particular species each week (Figure 4: Sand Martin and Swallow). This allows us to account for the variation in recording effort and gives us a more accurate picture of the number of observations each week. For Sand Martin, the number of list submitted that contained this species was very low during early March, rising steadily during April, and then stabilising. From May onwards, fewer than 20% of all lists submitted to Migration Watch contained Sand Martin. For Swallow, the proportion of lists with this species was much higher; from May onwards around 60% of all lists submitted had Swallow recorded. Figure 4. Proportion of visits when
species was observed
Swallow
|
|||||
Good
coverage was achieved throughout most of England and Wales, but
coverage in Scotland and Ireland reflected the sparse distribution
of birdwatchers in these areas (see map). 
|
||||
|
||||
