Sand Martin mid season report

In recent years I've blogged a lot about Sand Martins after each session or each week.  As the pattern of catching is pretty similar with early visits being mostly adults, mid season visits being a mix of adults and juveniles and late visits being mostly juveniles it all becomes pretty similar and I may as well say 'read previous year's report for these dates'.

This year has been vastly more successful than last year due to better weather and consequently river levels that are not over topping banks or flooding out burrows.  As a result we have:

- More captures for 2013 than we managed in all of 2012 although with increased effort in 2013
- 50% of the captures by this point in the season than we had in 2010 and 2011 with similar effort.

These figures reflect how poor 2012 was and how late the 2013 season is (about 10 days later for Sand Martins).  2010 and 2011 were exceptional in terms of productivity and occurred on top of good winters for returning birds.  2012 on the other hand had poor survival from the 2011 winter and a poor breeding season which has led to a lower population in the Lune valley.

As this is part of the BTO's Retrapping Adults for Survival programme (RAS) we are aiming to retrap birds from previous seasons to understand the survival of Sand Martins between years.  So far this year we have visited 3 large colonies and not managed to get into some smaller colonies due to windy weather limiting evenings we can ring on.  The retrap numbers from previous years are below:

Year of Ringing	Juvenile	Adult	Juv return rate	Adult Return rate
2009	0	1	N/A	0.5%
2010	2	0	N/A	0.1%*
2011	7	8	N/A	1%
2012	9	19	5%	13%

* Return rate calculated from total number of adults handled in each year and proportion caught this year.  As few adults were ringed in 2009 a higher proportion have survived than from 2010.

Following a good winter we typically expect 20% of adults to return and roughly 15% of juveniles although this varies from 2% to about 20% depending on various factors.  The 2010/11 winter gave us a return rate for adults of about 8% and the 2012/13 winter has given us a 13% return rate for adults.  As we caught about 1200 individual adults in 2011 we would expect (given the above rates) to retrap roughly 13 birds caught as adults in 2011.

Totals ringed so far this year are:
New Adults - 266
New Juveniles - 228
Retraps from previous years - 46
Controls - 1 UK ringed, 3 French ringed.

While nice to catch the foreigners it is hardly surprising given nearly every British Sand Martin will migrate through France on the way to winter in Africa.

Richard

Bearded Tits Do Well but Reed Warblers Falter

Bearded Tits are having a good season at Leighton Moss RSPB Reserve. To date we have caught 24 juveniles. This compares with only 17 in the whole of  2012 and what is normally the best  time for catching is yet to come. Both first and second broods seem to have done well. We ringed 21 nestlings  from five broods in our wigwam nest boxes. To date we have caught 8 of these with all five broods represented. The broods obviously split up fairly soon after fledging for yesterday we caught three of these  all from different broods.

Juvenile male Bearded Tit

Bearded Tits  form apparent pairs  a few weeks after fledging. This was well shown by a pair of adult birds caught together this week with consecutive ring numbers. They had been ringed together on June 11th 2012. They were either re-trapped or sighted together on five occasions during the autumn and winter and were still together this week. We have had many similar observations over the years.

To date we have either sighted or re-trapped  ten adult females and seven adult males and again the best period of re-trapping and sightings on the grit trays is yet to come. Of the 17 ringed as juveniles in 2012 nine have already been reported this year, suggesting good survival. Of the other adults two are in their fourth year

Reed Warblers though appear to be either down in numbers or late in their breeding or possibly a combination of both. With similar effort between years by June 26th 2012 we had caught 77 adults but this year we have caught only 33. It certainly has been a late season this year so it will be interesting to see what the next few weeks bring.

John

Redpoll and Siskin Recoveries

The results of our spring garden ringing of these two species which were caught in unprecedented numbers, have started to come through from the BTO.

Lesser Redpoll
Birds ringed in late autumn or winter from Surrey, Sussex, Suffolk and Derby were caught in our area in spring. While one ringed in West Lothan in September was also caught.  These reports fit in well with other recoveries and show the wintering area of our spring passage birds to be mainly in the south of England

Siskin
By contrast four of the reports of this species were from the breeding area , two in Northern Scotland and one in SW Scotland. This brings the total of  Siskin ringed or controlled in our area to 19 from Northern Scotland and nine from the SW Scotland.

Other Recoveries
Two belated reports from 2010 were of a Sand Martin in Spain in August making this our ninth report from this country. A Sedge Warbler from Belgium making it the fifth from that country.

John

Nest Boxes and Bearded Tits Do Better

Since my last post, which reported lower numbers and some deaths among early broods things have improved substantially. The weather has been kind with a warm dry spell and this has certainly helped. Both Great and especially Blue Tits have good broods and many are now fledging. There has been no further loss of young despite the lateness of the season. The only exception is one brood taken by Great Spotted Woodpeckers. Last year we had 5 woodpeckered. With broods being well fed they are not calling and so are not attracting the attention of woodpeckers. Pied Flycatchers have also done well and my impression is that young birds have grown quickly this season.

Kevin Briggs who is studying the caterpillars in a Lune valley woodland reports that numbers for the last three weeks have been very high and this has coincided with the period when the young are in  the nest. Hence the good results detailed above

 A Great Tit nest in Whittington woods is most unusual, on May 28th it  had 5 cold eggs, by June 6 it had 8 warm eggs which had hatched by June 14h but there were also 7 eggs and by June 20th it had increased to 8 eggs and there were still 8 young. Two birds laying in the same box ?

At Leighton Moss RSPB we have just started  this years catching of  young birds as part of our long running study of this  species. In 2012 with poor weather and high water levels we had a very poor season with only 17 young caught . Already this year we have caught 15 juveniles and ringed 21 nestlings so things are looking  much better and July is usually the best month for catching Bearded Tits. Sightings of the colour ringed adults suggest that survival over the winter has been exceptionally good.
John

A Poor Season in the Nest Boxes

My five nest box schemes are having a poor season.   Occupation rates are well down with a decline of 30% in Blue tits (65-45) and 23% in Great Tits(71-53) compared with 2012. Pied Flycatchers are very  similar to last year 13-14 but only occur in two woods. I have only 1 Nuthatch this year compared with three last year.

Both tit species are about a fortnight behind last year. Clutch size is not bad with a few low whereas others are normal.  Numbers are now feeding young. First indications are that brood size is rather low and at one site visited on May 29th three broods had succumbed no doubt due to the shortage of caterpillars  due to the unusually cold spring. This wood though usually has the highest rate of   total failures. It is mainly fairly young Ash. I visited three boxes in gardens. Blue and Great Tits had only 2 young each at the  ringing stage and the other Blue Tit had a brood  of six  all dead.

Hope the present warmer weather improves matters.
John