By Martine Stead
Curlew LIFE Intern, RSPB Insh Marshes

The thing about looking for a nesting Curlew is that if you can easily see a Curlew, it’s almost certainly not what you’re looking for.  A Curlew that can be clearly seen through your telescope is probably walking, or feeding, or just hanging around on the marshes, and not on the nest.  This is because a nesting Curlew is very well hidden.   Thijs Claes, our project leader, informs us that all you can usually see is the long curved bill sticking horizontally out through the marsh vegetation, and perhaps a little bit of the bird’s head and neck.

And, of course, to make the job even more challenging, the vegetation that Curlews favour for nesting is mostly the same height as or taller than Curlews – and is Curlew-coloured.  We do, however, have some tips to guide us: we know where nests were found last year, suggesting that there may be nests in similar areas this year, and we can observe the birds’ behaviour. If a predator such as a crow or buzzard flies over and the Curlews don’t start alarm-calling or trying to chase it away, then they almost certainly aren’t on nests yet.

We learn all this in our first week volunteering with the Curlew LIFE project at RSPB Insh Marshes.  There are six part-time volunteers who live locally, or travel regularly to the area, and me, the intern.  We start at the end of March, when the Curlews have already arrived back on the marshes from wherever they’ve spent the winter and are beginning to claim their territories with elegant, soaring displays of song flight.

Pairing up 

About 10 days into April we spot the first mating behaviour, and send an excited message to our WhatsApp group: ‘Curlew copulation!’.  This doesn’t necessarily mean that nest building will start immediately – the female may wait a few days before fertilising the eggs, and then a few more days before laying them.  But it means that the next couple of weeks are likely to be peak nest-making time.  Last year the project team found 17 nests.  With a bigger team this year, which includes researcher Alex, we’re aiming for 20 to 25 nests.

Once we’ve found the nests through our scopes, we have to plot them on a map.  There aren’t many landmarks – we find ourselves using descriptions like: ‘behind that slightly darker bit of grass in the middle of a larger bit of grass close to a damp patch’.  So translating what we can see from our vantage points through scopes into an exact location on the ground, over the 1,000 hectares of Insh Marshes, will be tricky.

Kitting out

A Curlew nest at RSPB Insh Marshes, found in 2022.

A Curlew nest at RSPB Insh Marshes, found in 2022. © RSPB Thijs Claes

Then we have to wade through the marsh to the actual nest spots (being careful to minimise disturbance and the time spent out there) to install cameras on slender posts.  These are to capture any predators near the nests.  Predators could be mustelids (such as badgers or stoats), foxes, gulls, corvids or raptors.  We also have to install temperature loggers, which monitor the temperature on the nest and can tell us if the nest fails, ie. if the eggs are trampled by livestock or eaten by predators.

And we have to measure the weight, length and width of eggs, using a delicate little set of scales and pair of calipers.  This is to give us an estimated hatching date.  The reason we need this is because when the eggs hatch, the chicks stay on the nest for less than 24 hours, and our researcher needs to get to them while they’re on the nest in order to tag them to track their progress before fledging.

It all sounds very challenging, but exciting.  It’s a huge step up from the extremely basic bird ‘surveying’ I’ve done before – counting mallards, mute swans and moorhens on the Union Canal in West Lothian for the monthly Wetland Birds Survey.

In decline

Curlews are regularly seen on the Forth Estuary, near where I live, outwith the breeding season. This winter visibility of Curlews in many parts of Scotland and the UK may lull people into thinking all is well with the species – but it isn’t. Breeding Curlew numbers in the UK fell by nearly half, 48%, between 1985 and 2015 – equivalent to 13.5% of the total world population. The reasons are complex: loss of habitat, predation, climate-related events such as flash floods. Insh Marshes is one of the areas in the UK where the Curlew population is relatively stable as opposed to continuing to decline. It’s really important, therefore, to try to work out what it is about this site that seems to work for these beautiful birds.

I’m one of the many people who became interested in doing more for wildlife conservation after many years working at something else (in my case, health research).  I took early retirement, began volunteering with RSPB Inner Forth reserves on the Forth Estuary, and started an HNC in Wildlife and Conservation Management at the Scottish Rural College (SRUC).  The HNC and volunteering experience gave me the inspiration to apply for the Curlew LIFE internship, and I was thrilled to be offered the place.  And to have the opportunity to live in a stunning part of Scotland, rich in wildlife, for the next six months.

First nest

On Monday 17th April 2023, Alex, the researcher, messages that he thinks he’s found a nest. I get the monitoring equipment ready and set up the camera, and go out to meet him with fellow volunteer David. The two of them walk out onto the marsh, with me giving directions over the phone. Then Alex’s voice confirms: ‘a nest – four eggs’. Through the scope I watch them do the measurements. It’s exciting to be part of it.

The following day, Tuesday 18th, I watch a bird for over an hour sitting in the one spot. Occasionally it shakes, wiggles and rotates, but never moves away. Could it be my first nest? After two hours, we’re almost certain, and again Alex and David wade out on to the marsh, knee deep in water at times. The bird flies off as they approach, and I keep my eye glued to the indistinct smudge of light-brown vegetation, in a sea of light-brown vegetation, where I think it had been sitting.

On the phone I guide them – forward, forward, a step to the left, forward. Alex’s voice on the phone: ‘a nest – four eggs’. You beauty. After they finish and depart, I keep watching, watching, through the scope. The bird flies in after 15 minutes, walks rapidly towards the camera but seems unperturbed by it, then paces out a wide circle, probing the vegetation for possible threats. It then crouches down and creeps slowly back towards the nest. It appears to count the eggs with its bill – one, two, three, four –, gives a little shuffle, hitches up its wings, and settles down on the eggs. I let my breath out. My first nest.