Assumptions?

So with 2 forgein Redpoll controls in one week maybe an assumption can be made that Common and Lesser are moving independantly of one another?

Lesser Redpoll number have reduced since last week but holding steady (pretty much all birds being caught are to be ringed). With the Belgium ringed bird we can perhaps assume that the population moving through has come from the East and South.

In contrast, Common Redpoll numbers have fluctuated over the last week and now more retraps are finding their way back into the nets. This could suggest that the Common are staying put for now, using the food source's supplied (in the form of a lot of Niger Seed!). We could also assume that the Common Redpoll migrated over from Scandinavian (Norweigen Ringed bird).

These are very much assumptions as there are many variables to apply to any kind of theory, e.g. birds switching flocks, migrating with different species etc.