Siren Song

Swanwick Lakes nature reserve used to be a very good spot for nightingales. Unfortunately, mirroring decline that is occurring across the whole of the UK, they have dropped off the radar on the site. This is extremely upsetting as they are one of my top birds but it has been a number of years since they have been recorded on site, so it’s fairly safe to say they are no longer present.

One of the most charismatic singers in the UK bird population, nightingale can be heard in the evening, babbling away within a dense thicket of scrub and is a song like no other. It can get confusing when the song thrushes mimic them (which they do incredibly well) but once you have heard one, it is something that sticks with you and, I think, always exciting to hear.

There does not seem to be any major reason why they disappeared at Swanwick but it may be changing levels of thick scrub, in which they nest, or other slight changes that pushed them away. I could be they just never made it back on migration.

There is plenty of decent habitat there now and we are working on some very specific management to encourage suitable habitat to develop. They need very thick scrub, usually densely packed, young growth of trees like birch or willow. This needs to be combined with a more open woodland that provides feeding opportunities for them. The northeast meadow and the yellow trail is ideal for this.

The ideal habitat type is really nicely described here by the BTO.

You can see that the domed effect is the ideal, with scrubby, youthful growth at the sides and a mature stand in the middle, providing bare ground and lots of invertebrates. This really focuses on the importance of scrub on reserves as it can often be seen as the daemon habitat, one to be swiftly removed when encroaching onto your flower-rich grassland.

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perfect Nightingale habitat in a nearby woodland

North East meadow at Swanwick Lakes is wood pasture so it’s a mix of flora rich grassland, changing with the dappled shade of the sparse trees, producing a woodland/grassland blend. There are pockets of scrub around the edges but I am keen to maintain some sporadic patches throughout. These dense little blocks will hopefully provide the perfect nesting opportunities for nightingales but are difficult to produce due to the pressure that we have from deer.

Weirdly deer are a contributing factor to nightingale decline, as well as many other species that rely on dense regrowth within our woodlands – dormice for instance. They browse everything to death and it’s at this time of year that they are most destructive as the plants have little reserves and the succulent new tips that do all the growing are promptly chomped off.

With our nice new scrubby habitat we are now going to tempt them in. The tricky thing with nightingales is that they are very site faithful and the males will return to the same spot year after year. There has been a ringing project in a woodland not too far away from Swanwick which has been monitoring a population for many years. Year on year the same individuals come back to almost exactly the same spot, a magnificent feat seeing as they went all the way to Sub-Saharan Africa and back. If I was illiterate so couldn’t read signs, had no map, GPS, compass, the likelihood of me walking to the northern tip of Scotland and back, ending up in the exact place I started, is fairly remote to say the least!

There is evidence to suggest that young males are attracted to the nocturnal song of established males (which incidentally becomes much richer and diverse the older the get as they learn more tunes). With this in mind I have started playing it through a speaker within the reserve over night. Hopefully a young male will fly over, hear it and investigate. He will hopefully then realise that his site has everything he needs and set up a territory.

Fingers crossed!

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