The Curlew LIFE project at RSPB Insh Marshes wants to create sufficient breeding opportunities for curlew and minimise the risk of nest failure and chick predation on the reserve. Local volunteer surveyors are supporting this work by locating curlew nests, following up on the chicks and managing a network of trail cameras to record predator activity levels. But what does it take to become an effective curlew surveyor? Locating a curlew nest requires commitment, but certainly also a sparkle of luck. Getting comfortable with a pair of binoculars and a scope is a must. This allows you to get up close and personal without disturbing the birds. Learning to interpret a curlew’s vocalisations and body language will also be helpful, so let me share a few top tips to enjoy the full curlew breeding spectacle in your area.
It is best to get familiar with the terrain before the birds arrive on the breeding grounds. If there are no suitable bird hides in the area, look for the best routes towards high vantage points with no or minimal disturbance to the birds. In an ideal situation you are hidden from sight, protected against the elements, and facing away from the sun in the morning.
Start observing curlew behaviours as soon as they arrive in large flocks. This is a brilliant way to establish a baseline of curlew behaviour, making it easier to pick out “unusual” behaviours related to breeding later in the season. These birds will act relaxed, using short vocalisations consisting of soft flight calls or the typical “CUr-Lee” call. Xeno-canto is a great website to get more familiar with all the curlew sounds. The birds will also hardly interact with other animals nearby. You can be certain there are no nests around just yet.
Pairs will gradually start to form. This is the ideal moment to distinguish males from females by comparing the bill size in relation to the head. Males, with the shorter bill, can often be seen following the females around. You might also start noticing a more elaborate sound, the curlew’s bubbly song. It is often combined with a circular flight above their territory, giving away a first clue of potential nesting areas.
After a few more days, curlew males become more impatient. They will start running after their mate, picking at her tail feathers, and flapping their wings more and more persistently. The latter behaviour is very conspicuous. Especially when the male jumps on top of the female and the white underwings flash like a beacon in the open landscape. Copulation has been completed and the eggs will be fertilised.
Now comes the time to pay closer attention to the female. She could start sitting down occasionally and wiggling her bum. This specific behaviour is called “nest scraping” and can be a good indication of the eventual nest location. As soon as the eggs are laid, it is likely you will only see one bird in the territory. The other bird will be well camouflaged whilst incubating the nest. This is a crucial time to locate the nest because the bird that is not incubating will also be staying in the near vicinity of the nest for a couple of days.
Finding the nest location later in the breeding stage gets tricky. There are still some opportunities to take advantage of however. Both sexes incubate the nest, and they swap shifts about twice a day. Look for a curlew moving slightly hunched down in a sneaky manner and hardly feeding. Observe the area around the bird, and chances are the incubating bird will suddenly pop up from the nest nearby.
Another situation that might work in your favour requires some assistance from avian or mammalian predators. Especially early in the morning mammals might still be roaming around in the breeding area. They can flush a curlew from the nest, who will then try to distract or even scare the predators away with mobbing behaviour. Instead of getting overly excited by the spectacle, a good curlew surveyor keeps his or her cool. Guess where the curlew might lead you next..
Adult curlews use vantage points such as posts or large rocks to look for danger later in the year. This is a good indication of the presence of chicks. They make themselves heard with sharp calls and perform mock attacks towards threats when their chicks are in danger. If this happens to be you while surveying, you should back away from the area swiftly.
Need more practice? Come meet us on our drop-in sessions throughout the breeding season at the RSPB Insh Marshes look-out. Our team will be thrilled to show you some curlew behaviours. Maybe we will even find a nest together!
Locating nests and broods allows us to gather knowledge on hatching success and specific predation pressures with detailed nest monitoring under license. With this information, we can the help consolidate the curlew’s future on the reserve and the wider landscape in Scotland.
Thijs Claes – Curlew LIFE project officer – RSPB Scotland, Insh Marshes