Monitoring Curlews For Curlew LIFE by Andy Scott

My name is Andy and I’ve spent the last 3 and a half months living at RSPB Geltsdale in Cumbria, monitoring curlews as part of the Curlew LIFE project. Curlew LIFE is a 4 year project managed by the RSPB, working with a number of project partners and aiming to stabilise curlew breeding populations in 5 priority landscapes across the UK. The internationally important UK breeding population of Eurasian curlew has seen a sharp decline over the past few decades and as a result, in 2015 the curlew was added to the Red List on the UK Conservation Status Report, denoting the highest level of concern. This decline is thought to be mainly due to loss of suitable habitat as a result of factors such as changing agricultural practices and afforestation, as well as predation by foxes, mustelids and corvids.
My role at Geltsdale has been to locate curlew nests and monitor them through to fledging. That sounds simple enough but, as I soon found out, finding a curlew’s nest requires a great deal of patience – and a bit of luck certainly helps!

Before starting as a residential volunteer, I’d been rather worried that I wouldn’t find a single nest, so I was hugely relieved when I soon found my first. I’d spotted a curlew in a field while driving along the track which leads to the RSPB’s volunteer accommodation, so I switched off my engine and watched through my binoculars from the side of the road. After half an hour or so, the moment I’d been waiting for came suddenly and unexpectedly – the curlew, head lowered, snuck speedily through the rough grass and virtually disappeared, her long curved beak just visible as she sat flat on the nest. Anyone who has spent time looking for curlew nests will tell you what a thrilling moment that is!

The next challenge was to locate the exact position of the nest and take a grid reference. Seeing an incubating curlew from a distance is no guarantee of finding the nest, as they are well camouflaged amongst the vegetation. It is often a case of keeping your eye stubbornly fixed on the spot where you have seen an incubating bird, or where a bird has lifted from, and stumbling over holes and hummocks as you try to make your way there without looking at your feet! If you’re lucky, you will find a loosely constructed nest of 3 or 4 eggs. I can vividly remember the joy felt at my first sight of them, with their green shells speckled with brown and their pointed ends. As I continued to locate nests over the coming days and weeks, that feeling never lessened.

Of course, there were many days when I spent hours watching curlews but failed to find any nests. Over time, I became more and more familiar with their behaviour. I watched for their furtive movements as they neared the nest, in comparison to the more relaxed behaviour when feeding and preening; I noticed how they reacted to potential predators, such as crows, as alarm calling is a sure sign of a nearby nest; I learned how they will sneak through the vegetation when getting off the nest before lifting some distance away, making it difficult to pinpoint the nest itself.

All this helped with locating nests, but even so there were some territories to which I had to make a number of visits before finding them, and some where I didn’t find the nest at all. It is crucial to minimise time spent in the nest area, so once the bird has been flushed from the nest, it is important not to spend too long searching (walking very carefully!) and come back another day instead. This can be frustrating when you know you are just metres from a nest, but curlew nests have a habit of disappearing and sometimes you have to admit defeat. In fact, even turning your back on a nest you have already found and moving a couple of paces can cause it to vanish!

Luckily, I had plenty of help in my searching. On the reserve, wardens Jen and Ian shared their extensive knowledge of curlew behaviour and let me know where they had seen potential nesting birds while conducting regular surveys (that is, if they hadn’t found the nest already!). The Curlew LIFE project site also covers a large area of farmland around Hadrian’s Wall, so the other source of assistance came from the farmers working with the project. The first farmer I met, Willie, clearly loved his curlews and both nests that we were monitoring on his farm were found by him. He even guided us to one of them with the use of some spray-painted arrows on his field! I was visiting 4 different farms as part of my role, but many more were being surveyed by a team of volunteers. Working together with farmers is a great resource for Curlew LIFE and allows important monitoring to take place on land where it otherwise might not.

After locating the nests, the next step was to monitor their progress. This involved putting up trail cams to capture incidences of predation, weighing and measuring the eggs to estimate hatching dates, and erecting electric predator fences around some nests. These were designed to keep out ground predators such as badgers, foxes and stoats. The fences were 25x25m and in teams of 3 or 4 we put them up as efficiently as possible, minimising disturbance to the curlews.
At Geltsdale we had very low predation rates at egg stage and so, towards the end of May and into June, we began to see the wonderful sight of newly hatched curlew chicks at our nest sites. Curlew chicks are able to feed themselves pretty much immediately after hatching. The adults job is to ward off predators as the chicks begin to wander about feeding on invertebrates, as they are very vulnerable at this stage.
After hatching we started conducting alarm calling curlew surveys. The adults have a distinctive ‘yak-yak’ alarm call when they have young nearby, so the surveys allow us to keep track of which birds have chicks and where they are. They can move a surprising distance even when young. The chicks are very well hidden at this early stage and more often than not there will be no sign of them when surveying. However, as they grow it becomes easier to spot them and eventually they can be seen flying around as fully fledged juveniles. At this stage they look similar to the adults but they have much shorter beaks and their plumage looks a bit fresher. Curlews need to fledge 0.42-0.68 chicks per pair per year to maintain a stable population, but many estimates of fledging rates are below this, so every fledgling counts.
In the past few weeks, as my time monitoring the curlews comes to an end, I have been very happy to see a number of fledged juveniles on my alarm calling surveys. Like me, they will soon be leaving Geltsdale, but hopefully they will return and play their part in maintaining a healthy breeding population. I will miss keeping an eye on them, but who knows, maybe one of the birds that I see this winter on the coast or in years to come will be one of my Geltsdale curlews.