Tuesday, July 21, 2009

Twite update

The RSPB's Twite Recovery Project fieldworker Nick Wilkinson has generously given permission for me to post his update on results so far this year from his and his co workers (Judith?) fieldwork. If anyone has any info on twite locally please forward it onto Nick (via me if you wish). As you can see from their efforts the RSPB are very serious about saving this seriously threatened species.

Several of our core sites appear to be a lot quieter now and have the ‘end of season’ feel about them, especially those that have experienced a high proportion of nest failures, even though there’s still another 10 days or so for new clutches to be started (going by Andre's latest first-egg date). We’ve found a few more nests in the last week, and with several pairs having recently fledged broods it will be interesting to see if many or indeed any of these carry on breeding.

A brief summary of our productivity monitoring so far:
84 nests recorded from c.50 pairs
nest outcomes: 36 fledged, 30 failed and 2 unknown
14 pairs have started second broods after fledging an earlier brood (3 of these 2nd broods have failed); 2 of these 14 pairs have now started their third brood (1 nest building and 1 at incubation)
it is important to note however that there are quite a few pairs for which we have incomplete histories, i.e. we’ve missed earlier or later nesting attempts, or missed the identity of the adults (a few cases) and cannot therefore confidently link nesting attempts
42 broods ringed, of which 40 have been colour ringed, 190 chicks in total
resighted 34 of 69 birds colour ringed in spring 2009, 30 of which we’ve found nesting
resighted 5 of 54 birds colour ringed as nestlings in 2008, 2 of which we’ve found nesting

One recent surprise was discovering a pair that had moved colonies (a distance of 1.3 km) after two failed nests. Another pair at one site moved quite large distances (>0.5 km) between each of their 3 or 4 failed attempts.



Please note some of the report has been withheld by myself due to the (remote?) possibility the specific naming of sites might lead to egg collector pressure, if anyone wants to see the edited section please contact me directly.

11 comments:

Goldon Gordon said...

Hi Nick
Are the causes of nest failure known ?

Nick Carter said...

Not sure but I guess the weather won't have helped!

Goldon Gordon said...

Hi Nick
Assuming thet Twite being upland birds the almost certainty of a poor spring and summer in the South Pennines should not affect them that drastically one would have thought ?

Is there any online data one can view on "normal" nesting success in the South Pennines? It seems rather important that surveys not only record what is happening to a species but why. If there is no data for this then it seems we are simply collating facts after the event and not attempting to change the factors involved. My thoughts are, is disturbance by walkers, sheep, farmers having any effect on nesting success, what foods could be in short supply during the key seasons of females devloping the eggs and once young are born.

I am not trying to critical of the excellant work that been carried out so far but it would be useful for more details on the "whys" were published in such reports or are they ?

Nick Carter said...

I'll forward your comments to the field workers involved

Goldon Gordon said...

Hi Nick
Thanks. Just to stress again my comments are not meant to be a critism just interested commnets

Alf King said...

Paul
One of the key aspects of the RSPB work is to try to determine the reasons for the decline in Twite numbers. It is suspected that the availability of suitable food is a major factor. This is why a number of us are still doing voluntary work with RSPB to help in this.

Outcomes will be published in due course i believe.

Nick Carter said...

Tell me about it Alf! How many fields have you got to survey? I had nearly 200 at the beginning but thankfully Jeff Cox has taken on half of these, rest assured Paul there is a tremendous amount of work going on!

Alf King said...

Only about 80 fields for me Nick but I am a bit of a softie as you know.

Where did you get this interim report from btw as I haven't seen anything before your posting?

Nick Carter said...

I have been in regular contact with Nick W and have kept him up to date with any twite sightings I know of, he e mailed it to me recently.

Goldon Gordon said...

It is suspected that the availability of suitable food is a major factor....I seem to remember this was stated as one of the suspected reasons for the birds decline a couple of years back and why the feeding stattions were set up ? Any other possible causes mooted yet ? Is climate change and the rise of the mean temp on uplands though to have any effect ? Last question is there any website or paper one can obtain giving more details of surveys and conclusions ?

Just again to stress I am not moaning about the effort involved by all, just trying to find some answers if possible.

Alf King said...

The availability of the right kind of food in the right place is the factor that is being studied very closely, in particular the distance that the birds can or need to travel to obtain the correct food.

Changes in agricultural policy may have an impact upon this. Also changes in climate will impact upon the plant species that occur in the present breeding areas. Despite their migratory behavious Twite do appear to be reluctant to relocate to new breeding areas so these existing populations are quite fragile.

I don't know of any publication, virtual or otherwise, that is currently available to interested parties.