Rings around the world

Nightingale at Gatwick Airport (Photo by Dean Samsudin, 2020)

Back in May 2016, myself and volunteer Donald were carrying out a reptile survey in the North West Zone when a sudden burst of bird song erupted near my head; a Nightingale was the last thing I'd expected to hear that day! This is a real stand-out moment from my time at Gatwick. I nipped back that same evening to make a recording (this being back in the era of a busy night-time airfield). Ambient noise didn't put this energetic songster off...

 

Sound only clip (no image)

Nightingales arrive in the UK around late April, having migrated all the way from their overwintering sites in Africa. Checking Gatwick's pan-species list, there are few previous records of Nightingale within the airport boundary. It seemed in 1987 the Hilton Hotel car park (around 3km from the current spot) contained some good scrub habitat which was suitable for their breeding, however in 2021 this area is now a stand of semi-mature trees.

Corridors of good quality habitat are important for dispersing wildlife, especially for highly mobile species such as migrating birds. The River Mole diversion project was completed in the year 2000, resulting over 20 years later in a 3.5km length of meandering floodplain meadow, bordered by sloping species-rich grassland, graduating into scrub and mature woodland. 

North West Zone biodiversity area

Since that record in 2016, I've heard a Nightingale in the same spot on the River Mole 5 years out of 6; could it be the same bird returning each summer? Another male then set up territory along the River Mole in 2020, about 1km further downstream. This year they've both remained on site late into summer, therefore are very likely breeding. Two Nightingales on one reserve doesn't make a population, but along with increasing numbers of Song Thrush and summer-visiting warbler territories, it could indicate that our scrub and grassland mosaic is coming into peak condition.

River Mole corridor, July 2016

Our biodiversity areas are only a short stint away from the Knepp Rewilding project, itself a large 1,400ha estate of grassland, wetland and scrub, 22km away as the Nightingale flies (for comparison our NWZ site is only around 40ha). It also contains a heck of a lot of Nightingales. Anecdotally, this red-listed species seems to be having a few good years, with other additional sites popping up nearby. Could this be an overflow of birds fledging at Knepp? When local wildlife watcher Dean alerted us that the second Nightingale was sporting a silver ring on its leg this year, it meant we could possibly find this out...

Penny Green in the River Mole grasslands

The bird ringing scheme, overseen by the British Trust for Ornithology (BTO), gathers data on the survival, productivity and movements of birds, which is important in understanding why populations are changing. Recovered rings have told some pretty surprising things over the years, causing our estimates of wild bird life-spans and travel distances to be revised. It is an intensive undertaking which involves a lot of special training. Fortunately several of the ecologists we work with happen to be licenced bird ringers!

Jon Middleton is an aviation ornithologist for Birdstrike Management Ltd, who visits Gatwick Airport as a consultant several times a year. In his spare time, Jon is an avid bird ringer and after hearing about our two Nightingale territories, he offered his help with Nightingale Territory 1; the original, un-ringed male.

Just as the night was drawing in, we had success in our single mist net; a male Nightingale caught and gently handled by Jon. This happened to be Jon's first time with this species in the hand, so it was a double celebration. The first ever Nightingale to be rung at Gatwick Airport!

A few nights later, it was the turn of another crack team: Penny Green the Knepp Estate ecologist and her partner Dave, who were keen to capture the second male and check the ring reference number. It was a more intrepid route on that evening, setting up our mist net at Nightingale Territory 2...

Photo by Dave Green

Success came once again just as it was growing dark, exactly as predicted by Penny and Dave!

With the bird in the hand, Dave could clearly see the silver ring. The priority was to note down the reference number, before taking additional measurements for biometric data...

Male being checked for breeding condition

An incredibly gratifying moment was when Penny checked the Knepp ring numbers from last year; this is a match for their records! In fact, this guy was rung by Dave himself in August 2020. Having this information confirmed is super high value, showing how these birds use sites across Sussex for breeding as well as migration stop-overs. As Penny put it, this is a fantastic link between our two projects.

A check of wing length and plumage condition

What a beauty....

A Knepp-rung Nightingale on the River Mole at Gatwick (photo by Penny Green)

A bonus Lime Hawkmoth extracted from the mist net

Two Nightingales, a luxury pack of chocolate digestives, and a group of very happy ecologists at Gatwick Airport on two nights in June.

Photo by Dave Green