With the curlew’s return, I’ve been able to spot one individual bird that made his presence felt last year. Without artificial aids like leg rings or wing tags, it’s not easy to reliably tell birds apart in the field, but this one cock has a crippled leg which sticks out below him when he flies and reduces his usually delicate landing process into an undignified affair. For the sake of unimaginative brevity, I named him “dropleg”. I think he was paired up last year with a hen who was killed by a hawk, and he then spent his time as a widower being thoroughly disruptive to all the other pairs, bothering them and contributing to a generally unsettled atmosphere on the moor. Mercifully, he left by the end of June and left the last remaining pair to bring off their chicks in peace. This is documented curlew behaviour; that those individuals or pairs who have failed in their breeding attempts will then grow restless and impede the breeding attempts of those who still stand a chance – a behavioural design-fault if ever I saw one.
I’m interested in this returning bird largely because it implies that curlews can be extremely faithful to their breeding grounds. My Shire Natural History Guide book (by Gerry Cotter) tells me that curlews are often loyal to specific areas or regions, but that precise site fidelity is less common. This bird has returned to the same field where he lived last year, and he has brought a new hen with him. I worry that he has come back not because he genuinely believes that he has a good chance of producing young on the Chayne, but more because some base, instinctive mechanism drives him to return without reason.
Having curlews on your ground in the summer is not an indication that they are being successful breeders, and they can return for decades without ever producing a fledged youngster. Their breeding strategy is almost the polar opposite of red grouse, which mass produce chicks during a short, furious life. Curlews live for decades and might produce a handful of fledged adult young over that time. It’s hard not to rejoice when they return to the hills, but the real rejoicing should be if they’re still there in July – a sure sign that the summer has shown fruit.
I’ve been studying the curlews on the Chayne in some detail over the past 18 months, and I have a heap of notes on their breeding behaviour. I only tend to précis the bulk of what I see on this blog, and when I was organising some things on my computer the other day, I decided to print off my notes in their entirety so that I would have a hard copy. I found that I had 167 sides of A4 on the subject of curlews alone, from descriptions of calls, displays and actual copulation to feathers, pellets and eggs. I can’t help feeling that 2015 will certainly add to that bulk.