Hello there, I have news of our bitterns this year. I’ve been given the OK to do this by Karen, our assistant warden. So make a cuppa, get comfy and enjoy.
This year we had three separate nests and they were all at slightly different stages – ie, the earliest, the middle one and the last one. How do we know this? From patterns gleaned from daily monitoring and from Dave, our warden, who put all the info together to form the ‘bittern picture’ this year.
Bitterns don’t necessarily lay their eggs all at the same time. They can lay up to seven eggs at 2 or 3 day intervals. Incubation lasts for 25/26 days – starting from the first egg. So in one nest, you might have birds with a range of ages.
Monitoring is very important and much information can be ‘worked out’ from what was seen. Monitor ‘extraordinaire’ this year was Gerald, regular visitor to Old Moor. He was in that hide every day for weeks and there wasn’t much that he didn’t know about each nest…although he may well disagree with me there. Flight patterns are tracked, as are the times of the flights. The flights are then recorded on a map (a different coloured pen for each bird) and times are written down in a log. Watching where the bitterns fly to, and fly back from, gives the wardens info as to where there must be good fish stocks for these birds.
Bird 3 in flight over the reeds...
When the chicks are young there are more flights, and sometimes suddenly all at the same time... which can be a bit confusing! Conversations at such times go something like this:
“Bittern!”
“Where?”
“Flying towards the owl box…Another bittern coming in from the right from the reedbed screen!”
“You watch that one, I’ll watch this one.”
“Bittern climbing the reeds in front! …Lost where the one on the right went…”
After reading that you can see it was helpful to have many pairs of eyes in the monitoring hide watching for the various bittern movements…Two to three people were normally monitoring every day.
Birds are timed as to how long they stay at the nest and their habits when doing so. EG: Bird 1 was always quick to leave the nest (on average she stayed 2 – 5 minutes), Bird 2 liked to wander a bit, climb the reeds and have a quick preen or a look before take-off (once she preened at the top of the reeds for an hour and a half…) and Bird 3 went all over the place, including wandering near the other nests. At times, she was then told unceremoniously to go away by the other adults.
Bird 2 enjoying part of her hour and a half preen. We even had time to phone Karen to say that it might be a good time to come along and watch if she could. And she did! It's also a very still day because the reeds are not moving.
As the chicks get older, the feeding flights become less frequent (ie the juvs can be left for longer) and this is when watchers started to look for signs of movement from the juvs. One way of doing this is to watch the reeds as the adults returned. If there was movement then it was possible to try to work out how many different movements there were. From this the wardens had a bit of an idea of how many juvs there might be. Another way is to watch the reeds for climbing juvs who are waiting for their mum to return so that they can be fed.
Adult female bittern fishing behind the reeds...ever elusive.
‘Reed watching’ becomes quite a skill and you get to learn what the different twitches in the reeds might mean. Reed warblers can do a very good impression of a ‘bittern reed twitch!’ Gerald worked out that the reed warblers often seemed to follow the bitterns as they walked through the reeds. We wondered if this was because the bitterns were disturbing the insects which meant a bit of an easy meal for the reed warblers. As bitterns walk through the reeds there are big reed movements in different directions. On a still day, it’s very easy to spot!
Bird 2 just about to take off after having a quick preen and a shake.
Photography also played a part in building up the bittern picture this year. Photos and videos helped us to recognise which bird was which, the different stages of the juvs and also whether or not the females were birds that had nested from previous years. All photos taken were just used for info by our wardens which is why you haven’t been seeing any, until now. Now that all juvs have successfully fledged and nesting has finished for this year, we are able to show you a few photos from the monitoring hide.
Another volunteer in the monitoring hide this year was Ron Marshall. He managed to capture a photo of a juv climbing the reeds. Thanks Ron.
In this photo you can see just how a bittern gathers the reeds together in a bundle so that they can stand on the reeds before climbing up.
The fabulous news is that this year we had 12 fledged juvs. Yes, twelve! They all had the same dad who did absolutely no work at all in feeding them. All the feeding is done by the female bitterns and they are now most likely having a very well deserved rest.
One day, Gerald saw the adult female + 4 juvs from nest one walk out in front of the monitoring hide. Wonderful! He managed to fit the 4 juvs in his photo. Thanks Gerald.
I’m sure that you will agree that this is very good news indeed and a big congrats go to our wardens and their team for creating a habitat in which the bitterns are thriving. Bitterns are still a relatively scarce bird (although numbers are improving). If you read this RSPB blog from last year, then you will learn that last year, and I quote directly from that blog;
‘A minimum of 164 boomers were recorded at 71 sites, compared to 162 boomers at 78 sites in 2016.’
It’s very good news that they are making a comeback and long may we enjoy having them at Old Moor!
One last video and it's of two of the juvs from nest 1 as they start exploring the big wide world...