Below is a short report on how things went with monitoring nest boxes on Landsort this year. Apologies for it not being in Swedish!!!!
Hope you enjoy!!
Report
to Landsort Bird Observatory Board on the monitoring of nest boxes in the
spring of 2016
Prepared
by Chris Sharpe – June 2016
Background
By
2008 a significant number of next boxes had been placed in the woods on
Landsort. Although some ringing of young in boxes has taken place in the years
since, there is no recent record on file of a systematic programme of
monitoring.
Within
the overall workload to be undertaken by Kay and me during 2016 it was agreed
that a review of occupancy should take place with young ringed at the nest
wherever possible.
As
part of the preparatory work a schedule of known nest boxes, their
identification number and approximate location was stored on file and made
available to us when we commenced our work for the season.
Methods
In
late April, a review of the computer file revealed that 261 boxes had been recorded
on the protocol. The location of each of these boxes was indicated
on maps held on the office computer, numbered 0 to 260 consecutively. Printed copies
of these maps were used to locate the boxes during field visits with notes
taken in a pocket book which were transferred to the computer protocol at the
end of each day.
All
nest box work was undertaken in the afternoon/early evenings after the eight
hour morning mist-netting sessions were completed.
Twenty-eight
boxes were examined on the 27th and 30th April, as a
sample, in order to determine how the breeding season was progressing. These
visits revealed partly built nests in some, probably Great Tit, with some
Starling already incubating eggs.
On
2nd May those boxes marked on the protocol as being designed for
Wryneck were visited and dry wood chippings placed in the bottom, this being
recommended as a means of helping attract the species to build. A small number
of other boxes were examined on the same day.
Thereafter,
visits on six further afternoons: 25th and 31st May and 2nd,
3rd, 5th and 6th June were undertaken to look
for and examine all nest boxes and ring any young that were large enough.
Additional
visits were undertaken on: 4th, 10th, 12th, 14th,
17th, 21st, 24th & 30th June to
check progress on late nests.
Results
Of
the 261 boxes marked on the protocol, the locations for only 259 were marked on
the maps stored on computer: boxes ‘0’ and ‘42’ having no record shown.
Of
the 259 boxes marked on the map, 11 were not looked for, simply due to a
combination of time restrictions and tiredness!! In total 248 boxes were
searched for (96% coverage). Of these, 20 nest boxes were looked for but could
not be found. Eleven boxes were located but were discovered on the ground,
either having fallen off the tree or the tree itself had fallen over.
Therefore,
a total of 217 boxes were located and in a good enough condition to be used for
breeding. This represents 86% of the boxes marked on the map. Of these 71 (32.7%)
were occupied this year.
A
summary of occupied boxes where chicks were ringed is shown below:
Species
| No. Occupied boxes |
Total young
ringed
|
|
Great
Tit
| 29 | 156 |
|
Blue
Tit
| 2 | 17 |
|
Marsh
Tit
| 1 | 4 |
|
Starling
| 13 | 48 |
|
Pied
Flycatcher
| 1 | 7 |
|
Robin
| 1 | 4 |
|
Tree
Sparrow
| 1 | 2 |
Discussion
A
total of 238 young of 7 species were ringed from 48 nests. Data gathered from
ringing young in the nest is of high conservation value. Much information is
gathered in this way that it is not possible to gather from routine
mist-netting. Exact location of breeding, clutch size and sibling relationships
are all known from nest box studies. In more detailed studies, with marking of
adults, the relationship between pairs can also be determined, as can site
fidelity and longevity, laying dates and fledging dates etc.
As
at the time of writing this report, 20 individuals ringed in the nest had been
re-caught during routine mist-netting, giving some indication of fledging
success, though more detailed study would be needed to draw any firm
conclusions from the work of just one year. The 20 young (4 Starling, 14 Great
Tit & 2 Marsh Tit) come from just 8 nests. The four Starling came from
three different sites, while the 14 Great Tit came from four broods: six of the
seven ringed at Box 101 have been re-caught, four of the six at Box 4, three
out of four from Box 60 and just one from the brood of seven in Box 18 has been
re-caught.
Nest
box work can be challenging; mosquitos, thorns, bogs, tangled under-growth and
elusive nest boxes, all add to a sense of frustration especially after early
morning starts. There is no doubt however that it brings many rewards. It
provides a great opportunity to wander through a beautiful island and there is
a great sense of achievement in finding the boxes. Where else can you open a
nest box and come face to face with a Viper!! The main benefit though is the
conservation value of the work.
Although
some of the nestlings have already been re-caught it is anticipated that there
will be more caught as the autumn progresses, adding to the already
considerable value of the work undertaken.
Working
on nest box studies is a valuable means by which someone with an interest in
bird research and ringing can gain experience. The work done in 2016, although
comprehensive in terms of coverage and birds ringed, was not the most detailed
of studies that could be undertaken. Most boxes were visited on only one or two
occasions. More intensive research could add to the value by studying such
things as foraging rates and productivity (ratio of eggs laid to young hatched
and young fledged). Long-term studies add to our understanding of laying dates
and site fidelity (do adults use the same boxes year after year). The work of
2016 represents a welcome return to monitoring nest boxes on Landsort. It was
not the most detailed study that could have been done but it does demonstrate
what can be achieved.
Approximately
50 hours work over a six week period (mainly during 2 weeks) has produced good
research information.
At
the end of the breeding season – probably as late as early November when
general ringing has become less busy it is intended that the boxes will be
revisited to empty them of old nest material and put back on the trees those
that have fallen off.
Note,
that as not all boxes were emptied of old nest material in either 2014 or 2015
it was not possible to say with certainty whether a nest was from 2016 but
failed, or was from an earlier year with no nesting attempt in the current
year. Emptying all boxes at the end of each breeding season (with the exception
of Wryneck & Nuthatch nests) will allow for an evaluation of nesting
attempt versus nesting success.
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