You stated that the BTO stopped the ringing of House Sparrows back in the 60's as they were considered invulnerable, yet DEFRA are now shooting them!!! How is that allowed when they are in such decline?!
Sue.
Yes, BTO discouraged ringing house sparrows with penalties - more in a mo.
Are DEFRA really shooting them ? Still ? Did they ever - or did they encourage their control when they were abundant in much the same way that Mao launched a campaign against birds in China about 1960 ? I find that hard to believe of DEFRA, even of "the most incompetent ministry there ever was, bar none". For a start, DEFRA wouldn't actively involve itself in something like that except on their own premises. Even there, they would engage contractors because their own staff would not have the proper training and comics, sorry, typo, certificates. They would then not admit that any cull had anything to do with them.
In any case, DEFRA's activities bear no relation to what ringers are doing. Indeed ringers are providing some of the information that may be used to try to prevent DEFRA's actions.
Back to the spugs :
Ringing in general continues to yield useful information because the situation is not stable, is constantly changing. Even if, for certain species, we think we know a lot (questionable), the situation may change in an unexpected way. John Morgan's example is a classic. One ringer told me that in the 60's they used to take everything else from the nets and then lift the pockets open gently so all the sparrows - often dozens, were freed. Potential information on population declines that occurred thereafter was lost. This is a classic example of "we don't know what we don't know" - so we have no idea if we might have gathered important information. However I can say that we still don't understand house sparrow declines - there are a huge number of question marks over why ? so we don't really know what to do.
Consider - about 1990 many farms in East Lothian saw massive declines in house sparrow. On my own farm c.150 went down to c.3. After several years they started to recover to well over 50 today. I attributed this to the end of keeping cattle. That change in practice occurred on many E.Lothian farms. Then I found out that two of my neighbours who had not stopped keeping cattle suffered similar patterns of decline. One lost their sparrows completely, with a few returning in the last year or so. All that time their stock husbandry remained much the same. The other saw more or less exactly the same pattern as me (even though cattle were later removed - 1998 - but some sheep, hens and occasional pigs have been there).
Another example of unexpected changes has been seen with blackcap. This warbler has recently started wintering in Britain in quite significant numbers. Ringing information has shown these are not British breeders. They have migrated from west central Europe - typically Germany. Our breeding birds still winter in Iberia. This kind of information is important in identifying what management is required to protect these birds. Despite birds wintering here, our breeders are still entirely dependent on Iberia, so we must worry about conditions there (and vice versa). The Germans must now consider the UK regarding their breeding population (and vice versa).
Ringing of all species, even those that we know a lot about the population biology for, provides a continual picture of what is important for them. For some kinds of information the only alternative is the nest record scheme, which is equally valuable but perhaps more intrusive. Combined the two schemes provide a cross check on each other - validation of the data increases our confidence in it. This year I expect to see low proportions of young birds in our ringing results. Why - terrible summer weather has perhaps affected breeding. Am I right ? How bad ? Which species ?
On the latter point I suspect yellowhammer and skylark have been particularly badly affected. I would like the politicians holding the purse strings to help with conservation efforts on those species. How can we persuade them ? For yellowhammer we will get ringing data - hard facts to show them. For skylark we will not (we are not good at catching them).
Then again - maybe my expectations are wrong (I hope so). Ringing will tell us from the proportion of young birds caught. It is impossible to age yellowhammer and most small birds without catching them. Once you have caught them and aged them, you put on a ring so you can identify them again. That eliminates the chance of counting a biased sample of the same birds twice. For example, it is not unlikely that young, inexperienced birds might be more likely to get caught again, giving the impression of a higher proportion of young birds than is really the case. Then there is all the other information that being able to identify a bird allows - movement, changes in body condition, validating ageing and sexing methods, age ranges within the population (most small birds cannot be aged specifically after their first full moult).
Yes, these research methods are intrusive. What cost-benefit balance to choose is entirely subjective. Yes, it is an enjoyable hobby, which is a danger in itself. Ringers (I have only just started training having been an assistant for several years) are taught to put the bird first. Observations I have made while doing one particular BTO project have caused me to ask the BTO to re-examine one aspect of that project. By next season I expect to have further advice on that. The BTO is not going to reject a re-design of the data collection outright. They may seek better information from a better designed study.
I hope we all question our own activities all the time. Your input is a valuable reminder to stay on the ball, to think. I hope we don't need that reminder, but I wouldn't presume to ask you just to trust us

Six rings on a bird is excessive. Could you try to note the combinations, presuming it is a colour ringed bird, and report it directly to the BTO ringing unit noting your concern ? *the latter is necessary in case the record is dealt with by inexperienced or temporary office staff who are not aware of all rules for field work.
Mike.