Spotted flycatchers have declined by almost 90% between 1967-2012, making them fairly rare breeders in the UK. Although they're quite drab when it comes to plumage and song, it's hard not to be impressed by their patience as they perch on an exposed branch, eyes fixed on potential prey, before flitting off and catching insects in flight in an impressive aerobatic display. During an isolation stint at my home on the Bucks/Ox border, I was really happy to see three flycatcher fledglings in the yew tree! At first from a distance I thought they might be robin juveniles, but it quickly became apparent that I was wrong when the parents starting regularly visiting them with freshly-caught flies.
We've been treated to a huge amount of variation in species during recent ringing sessions, meaning lots of first-time-handles for me!
It's been an incredibly busy past couple of months, but I'm relieved to say that today I ringed my last brood of chicks of the field season. In total that makes just over 550 chicks of 4 different species!
Here in Wytham, we mark all chicks nesting in the boxes with a BTO metal ring, each of which has a unique number-letter code and is placed on their leg. They are extremely light so as not to cause any discomfort to the birds, comparable to the weight of a mobile phone in our pockets. The rings provide really useful information, allowing us to collect data and determine the birds' movement and survival when caught again in the future, both in Wytham and beyond. Additionally, we place a PIT tag onto the second leg of all great tit chicks. These are special rings (also extremely light) which allow a bird to be identified without even having to catch it. They are essentially small magnets that don't themselves actively emit any information, but when they pass through a specific signal they disrupt it in a uniquely identifiable way. This allows the birds to be identified without capture, for example, at specialist bird feeders and nest boxes, therefore making it possible to really accurately track the movements, habits and life histories of individuals.
I've really enjoyed this field season, and have learned much more about how the breeding phenology and habits of these four woodland birds operate. For now I'll take a break from fieldwork, returning to more of the analysis and writing-up of my DPhil project, but I'm looking forward to doing the season this time again next year!
Today I was assisting at an undergrad field course ringing session. Normally in Wytham we ring in the winter, using short lengths of mist nets around feeders with the aim to specifically catch and mark great/blue tits. But today we set up many more nets dispersed randomly around the woods, and unsurprisingly we caught many species that I've never before handled! This included lots of summer migrants, such as blackcap, whitethroat and chiffchaff, but most excitingly this sparrowhawk!! We ringed the individual nice and efficiently and, as always, without any harm to the bird..
Fieldwork has been very full on recently, and with lots of chicks hatching it shows no sign of slowing down any time soon. So I made sure to make the most of probably one of my last half-days off in a while by scouting out a fox den!
Less than a week ago, I saw movement in the distance in an area of scrub that borders the edge of Bean wood (where my fieldwork is). Looking through my binoculars I could make out three fox cubs that only looked 6-8 weeks old, and so they would have only just started venturing out of their den. So today I crept into the area where I suspected the den to be, and after a bit of searching spotted two fox cubs sunbathing! I continued to stalk very slowly, and without them noticing me a third came out of the den.
It had to have been one of my favourite experiences with wildlife for a while. Occasionally the cubs noticed I was there, but they seemed much more interested as opposed to scared (particularly of my camera shutter!). In all, I was with them for about an hour - I’ve put together a selection of my favourite photos from the session!
Not very good photos at all but I was really pleased to hear and see this garden warbler during my fieldwork today! They have a really beautiful song, similar to a blackcap's but a little longer and lower (at least in this case!). Although it doesn't look like the most exotic bird, it's always nice to have a close encounter with a species that you've never been close to before!
Today I found the first chicks of the field season at Wytham during my rounds in Bean Wood. Weighing a little over 1g each, if all goes well these chicks will increase their weight by up to 15-fold over the next couple of weeks. I'm hoping that the impending rain that's forecasted won't be too detrimental for the early broods!
As part of the DPhil I have started this year, I have joined the Edward Grey Institute of Field Ornithology (http://egi.zoo.ox.ac.uk), which is a leading institute in the study of birds! The EGI has monitored the breeding population of cavity-nesters (mainly great and blue tits, but also a handful of nuthatches, coal and marsh tits) in Wytham Woods since 1947, collecting really standardised data on these birds every year. This makes it possible to have tonnes of information on how successful the birds are, the timing of their breeding attempts, where they are, and how they are related to the rest of the entire population. In turn, this means we have really useful data that can be used by researchers to ask wider questions about ecology and evolution (like I am doing with questions about the consequences of population age-structure!).
However, it's no mean feat to collect this data! There are over 1500 nest boxes in the woods, and this year it has been split into 7 rounds for 8 fieldworkers. In my round, I have a little over 150 nest boxes which I will be keeping track of and collecting data from over the next couple of months. So far, this has just been visiting the boxes once a week to check how advanced the nest-building is. But today I'm very pleased to find the first eggs of the season!
The birds lay one egg a day, and so this box with three eggs means the lay date was 4th April. I weighed the eggs to identify the species (as well as it being data for potential future research), where great tit eggs generally weight greater than 1.3g, and all other tit species that take up the boxes weigh less. The blue tit in this nest will probably continue to lay for the next week or so, and then will begin incubation for ~13 days. I'm looking forward to finding many more eggs in my rounds at Bean wood, and hopefully some chicks soon as well!
It's been nice to hear a couple of green- and chaffinches singing loud in the garden over the past week. These two species tend to breed a bit later than some of our other garden visitors (like the tits, robins and blackbirds), generally beginning to build their nests later on in April. But clearly that hasn't stopped these males to start pairing!
A blog of my ideas, photography and research of the natural world.