Thanks to volunteer Phil for his report and photos
This is the time of year when at Pulborough Brooks we like to feature nightingales, those legendary songbirds. A few of these increasingly scarce summer migrants take up residence at Pulborough every year. Sadly under lockdown I live too far away to visit so it looks like I’m going to suffer a nightingale free year so instead this article is a reflection on what makes these birds so special and how they are doing at Pulborough Brooks.
First here is a photograph of a nightingale on the path in Adder Alley.
Nightingale in Adder Valley (Phil Thornton)
This is remarkable for 2 reasons. First is that for such an iconic bird it looks completely unremarkable, like a robin but without the striking red breast. Secondly the bird is in the wrong place, being out in the open on a path, when textbooks say that nightingales skulk out of sight in bushes and sing beautifully. That is true much of the time, but during the day they sometimes perch, sing and forage openly. Birds clearly do not read textbooks.
The nightingale is classified as a “chat”, a family of small robin-like insect eating birds which also includes, stonechat, whinchat, wheatear and redstart, some of which crop up at Pulborough during migration but do not stay to breed. Most of these species including the nightingale are summer visitors from Africa.
Male nightingales arrive before the females to set up a territory and are thought to be faithful to particular breeding sites, but only so long as the habitat remains suitable. However, maintaining suitable habitat as plants, shrubs and trees grow and are subject to browsing by animals requires understanding and careful management.
Nightingales build their nests close to the ground in dense thickets, but require bare ground nearby with leaf litter and a complete canopy cover of vegetation so that they can forage out of sight for insects. This type of habitat can be provided by deep hedgerows or areas of scrub typically with blackthorn, hawthorn and bramble growing. But as the bushes grow more leggy and start to mature into trees, and as deer browse at the edges of this structure so the edges thin out and becomes less attractive as cover, and this needs to be rectified by promoting new growth at ground level. Some animal grazing can help that process, but too much is counterproductive.
These effects of too much growth, deer browsing, and insufficient regeneration started to become clear along Adder Alley 2-3 years ago.The scrub area between the path and the Pig Run had been a nightingale hotspot for several years but in reality it was becoming less attractive and nightingales were seen there less often. So a rotational hedgerow and scrub management plan was introduced with a key aim of making sure there would be sufficient good quality nightingale breeding habitat on the reserve. Some of the work may have looked rather drastic but hopefully it will eventually bear fruit and continue to provide a framework for keeping the habitat in good condition for nightingales going forward. This work will also benefit other species, for example the population of the scarce brown hairstreak butterfly on the site relies on the availability of new growth blackthorn.
For readers wanting to understand habitat management for nightingales in more detail there is an interesting guide on the British Trust for Ornithology website.
https://www.bto.org/sites/default/files/shared_documents/publications/conservation-advice-notes/2015/conservation-advice-notes-001-nightingalesb.pdf
The lack of understanding of how scrub should be managed for nightingales is thought to be a major factor in the 90% decline in the UK population of nightingales in the last 50 years. Current estimates suggest a population of only 6700 singing males, which represents a loss of approximately 60,000 over that period.
My spies in the Pulborough area advise that there appear to be at least 4 singing males on the reserve this year which suggests that they are at least holding their own when compared with 2019.
Nightingales are famous for singing into the night. This is because they usually migrate at night, so it is the perfect time for a singing male to advertise his territory to a female passing overhead.
Personally I much prefer the fluty more joined up song of the blackbird, but there can be no doubt that the nightingale has a far greater ability to make an extraordinary range of sounds, more so than any other songbird, and that is why it is so special. It has a very large repertoire of phrases notes and other sounds which are sometimes repeated. This means it is sometimes possible to mistake a song thrush, which typically repeats short phrases, for a nightingale. However, once you have heard a nightingale a few times it becomes unmistakable for its sheer variety.
Once males have paired with a female they will generally stop singing in the night, but may sometimes sing during the day quite openly to reinforce their territory in the same way that other birds do. Here is one singing near the top of the Pig Run a few years ago just a few yards away and seemingly completely unperturbed by my presence.
Nightingale singing (Phil Thornton)
There is much folklore surrounding nightingales and it is mentioned many times in literature. The idea of a nightingale singing in Berkeley Square, according to the old Vera Lynn song, is a deliberate fantasy, and yet why should it not be true? Two years ago, while visiting Berlin, I was nearing the end of an evening walk through a park at dusk when nightingale song suddenly erupted from a nearby bush – a truly memorable occasion. I subsequently discovered that the presence of nightingales in Berlin parks is well known.
Hopefully we can manage our scrub effectively at Pulborough going forward to create more memorable occasions with these special birds.