Introduction by Jim Day
Brenda Cook, British Trust for Ornithology volunteer and bird ringer, has been ringing and recording birds at Blashford Lakes with fellow BTO volunteer and lead ringer Kevin Sayer for many years now, but the nest box monitoring scheme is her own project and relatively new having started in 2012. She and her stalwart HIWWT volunteer assistant, Jacki, were actually in today checking, cleaning, repairing and replacing nest boxes where needed ready for the 2019 nesting season so this blog, based on her report which was e-mailed to us on New Years Day, is quite timely!
I believe it makes interesting reading so have sought Brenda’s permission to publish it here. If nothing else it may help to explain to all those visitors who are curious as to why our nest boxes are so (relatively) low – basically so Brenda can see into them without the need for a step ladder, solving a H&S conundrum, generally making life easier and the birds don’t care anyway! Thanks to Brenda for her hard work and for sharing the data collected with us:
BLASHFORD LAKES NESTING REPORT FOR 2018 – by Brenda Cook
Each year since 2012 as soon as Christmas and the New Year celebrations are over I always begin to think about the Blashford Lakes nest boxes and it was the same this year in 2018. Spring would soon be arriving and the birds would be beginning to look at the nest boxes in preparation for building their nests. I wanted to do my usual checks of cleaning out, repairing and replacing the very old rotten boxes as soon as possible. The Young Naturalists (YN’s) had kindly made 12 new boxes this year which I planned to use to replace old boxes or site on new trees.
It was on January 13th that Jacki and I found the time and suitable weather to go round and do our checks in preparation for the breeding season. We eventually ended up with 62 boxes to start monitoring. The boxes have a variety of hole sizes from 25mm – 32mm to suit either Coal Tit, Blue Tit, Great Tit or Nuthatch. Each nest box now has a metal plate fitted around the hole to prevent predation from particularly woodpeckers and squirrels. This has been very successful. I also have a couple of specially made Tree Creeper boxes which I am hoping one day will be used for nesting.
The first official nest box check took place on 14.4.18 and we found nest building taking place in many of the boxes. There were even cold eggs in 3 of the nest boxes. I knew that by the following Saturday there would be females incubating eggs. The first naked and blind chicks were found in 2 boxes on 29.4.18. This was much earlier than in 2017 when we had to wait until 22nd April for our first chicks. I was keeping a close eye on the new YN’s boxes and pieces of moss were found in a lot of these boxes, but not all continued to form a complete nest.
I took photos at different stages and sent these with updates so Tracy would be able to inform the YN’s of the progress in their boxes.
The early weather was not perfect for the nesting birds, but then as we all know conditions improved and it became hot and dry which meant the adults did not have to do so much brooding of the growing chicks and were able to spend their time collecting the plentiful food. Chick survival rate was good and also the numbers which eventually fledged. A total of 204 Blue Tit eggs were laid in the boxes and 169 chicks were ringed. Great Tit females laid 141 eggs and 102 chicks were ringed.
I was able to show the YN’s a little about nest box monitoring on Sunday 27th May. They came round with me in small groups and we looked in nest boxes to see different stages of nesting and saw the difference between a Blue Tit and Great Tit nest. The Blue Tits line their nests with lots of feathers and the Great Tits line theirs with hair, fur wool and other soft material, though rarely feathers.
The YN’s also saw adult birds in the hand and chicks at different stages of development. They actually saw me ring some chicks which they all seemed interested in, so maybe there will be some future ringers among the YN’s!
A total of 42 nest boxes all reached the egg stage which is from when the BTO like me to keep records to enter on the new online DEMON data system. Out of the 12 new YN boxes 6 of them fledged young successfully. The last check for fledging from the final nest box took place on 7.6.18.
I also found time to monitor a Blackbird’s nest in a bramble bush and 3 Reed Warbler nests during the breeding season at Blashford.
These are the results from all the nests I found at Blashford Lakes in 2018.
|SPECIES||NESTS||EGGS||PULLI RINGED||PULLI FLEDGED||NEST SUCCESS||NEST FAILURE|
I am always interested in re-trapping the females who are nesting in the boxes. I managed to trap all females from the boxes monitored. This is time consuming, but if done at the right time provides me with data on their age, their survival rate how many eggs they lay, how many they manage to hatch and the numbers of chicks they have successfully fledged. I always take measurements of these birds. The most interesting is their weight. If the birds are of a good weight they have prepared themselves well for breeding. They have managed to find plenty of food and survived well over the Winter months. These birds are likely to lay more eggs, be good at incubating, and are fit enough and have enough energy to be able to feed their hatched young through to successful fledging. The heaviest female Blue Tit this year was 13.8 g and the heaviest Great Tit was 21.9g. I also managed to trap a few of the males and would like to try to trap more next year to add to my data and see if any have the same mate.
I have discovered over the years that once females have used a particular nesting box they like to use it the following year. If another female has got there before them they nest in a neighbouring box and then return to their original box if possible the next year. The 4 oldest birds I had nesting this year were born in 2013 and most of them I have trapped each year while nesting.
Another piece of interesting data is that 5 chicks I have ringed in boxes over the years are now using nest boxes to produce their own young. 2 of these were ringed in 2015.
We have done a couple of mist netting sessions in November to help collect data for a new project on Blue Tit moult for the BTO. This has also provided me with some re-traps of this years fledged chicks. This data shows me which young are surviving and I hope to find them nesting in 2019. There were 3 Blue Tit chicks from Box 102. 2 from Box 6b. 1 from Box 107A. 1 from Box 110 and 1 from Box 113. There were also some Great Tits re-trapped and these were 1 from Box D. 1 from Box 5A. 1 from Box 101 and 2 from Box YN 11(TB.) There was also 1 Nuthatch chick re-trapped from the four I had ringed.
We also caught 2 Blue Tit chicks from Box 110 on 29.8.18 and 16.9.18 during one of our mist netting sessions near the Lapwing Hide. The second bird was undergoing post juvenile moult. A Great Tit was also re-trapped on 24.10.18 and this bird was able to be aged as a 3M and was from Box YN 9(WH).
I am really pleased with all the data I have managed to collect since 2012. Each year I have increased the starting number of boxes which I begin monitoring. I have records of dates when the birds begin to nest, lay their eggs, their young hatch, the numbers of chicks I have ringed and finally the numbers fledged. I have evidence of re-trapping females in the same nest box each year and now there are chicks I have ringed who are using the nest boxes to build their own nests and have their own young.
Below are charts showing the results of my NEST BOX MONITORING for Great Tit, Blue Tit and Nuthatch from 2012 – 2018.
I always enjoy doing the nest box monitoring, but would not be able to do it without the kind permission and help from the people mentioned below.
I would like to say thank you very much to John Durnell and Bob Chapman for giving me permission to monitor the boxes. To Jacki Griffiths for helping me again this year and to two of my friends who filled in when Jacki was on holiday. To Jim Day who kindly lends me Jacki from her usual Saturday voluntary jobs and lastly to Tracy Standish, Geoff Knott and the YN’s for making the new nest boxes.