Small mammals of Gatwick

Recently published research by the Mammal Society has revealed some very worrying news; the UK's small mammals are not faring as well as we thought. Species previously not known to be at risk, including Weasels, Stoats and even our seemingly ubiquitous voles and shrews, are suffering long-term declines and are in need of conservation action. It is now estimated that 1 in 4 species in the UK are in real danger from extinction.

We have known for decades that UK landscapes are highly pressured, nature-depleted places in which to live, but the scale of the problem is still coming to light. Small mammals are important, and usually abundant, parts of natural ecosystems. Their loss will impact our habitat dynamics, ecosystem stability and populations of other wildlife which depend on them. 

Publication by the Mammal Society

Intensive management or development of land leading to the disappearance of long, naturalistic areas of vegetation which these species need has taken its toll. We are fortunate that buffer land around an airport can provide resources for a wide range of small mammals: Harvest Mice, Hazel Dormice, Weasels, Stoats, Common and Pygmy Shrews, Field and Bank Voles, Yellow-necked and Wood Mice have all been confirmed on our sites. We have also identified opportunities outside of these areas, with a new road-verge management regime providing those all important long-grass areas.

I have been playing with some new lens attachments for trail cameras, targeting better close-ups of small wildlife. I set up a Browning trail camera on an old log pile within our best scrub and grassland, which looked to be a hub of activity due to all the niches and crevices. It is always fascinating to observe different species interacting with each other. After trawling through a lot of footage, the results are in; I can officially and scientifically state that all small mammal species are Very Cute.

If you happen to own or manage a very manicured piece of grassland, then perhaps think about setting aside some longer grass areas, particularly at the base of shrubs, trees and hedgerows. You could just mow your patch once a year in early spring, before the wildflower species get going. Collecting up the cuttings and leaving in a pile in a corner is very beneficial to insects, mammals and reptiles too.

Thanks for reading... here are a few Gatwick Bank Voles, mice and shrews for your enjoyment.

Long-horned flights

 A brief update on Gatwick's colonies of Long-horned Bees (Eucera longicornis) during the 2021 field season.

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

Gatwick Airport's Annual Biodiversity Review 2020

Gatwick Airport’s Annual Biodiversity Review is here again, and despite the challenges from Covid-19 in 2020 we’ve been able to pull together loads of fascinating information and records of our local wildlife. A huge thank you to everyone who contributed to the project in 2020. 

Gatwick Airport Annual Biodiversity Review 2020

 

The importance of wildlife records

During my first undergraduate lecture (15.5 years ago!), the lecturer asked us to define the subject 'ecology'. Most responses were something like 'the study of animal interactions with their given habitats'. After correctly identifying which of us had specifically signed up for Zoology, she reminded us of all the other living kingdoms which also form the backbone of ecosystems, including the higher and lower plants, fungi, bacteria and other groups of primarily microscopic organisms.

A breakdown of the species group records for Gatwick Airport's species database (2020)

To be honest, this bunch of fresher students were probably only thinking about animals with backbones. Human interest tends to skew toward big and charismatic life forms, but really its the small and most abundant stuff which forms the bases of functioning ecosystems. The chart above reflects this in a way, with around 50% of Gatwick's species records made up of invertebrates, 30% of the higher and lower plants, 12% are fungi and slime-moulds, then whatever else makes up the rest (microscopic organisms sadly not yet included here).

Floristically rich habitats (like the River Mole floodplain near Brockley Wood) support large communities of invertebrates, fungi and other organisms.

Ecosystems are rarely static and are vulnerable to all sorts of pressures; we can use wildlife records as a measure of the current health and condition of a given habitat. A pan-species list (the term invented by Mark Telfer) is a comprehensive inventory of species occurring within a given geographical area, helping us to build an accurate picture of that ecosystem. With help from the Sussex Biodiversity Record Centre (SxBRC), we have finally collated a list of (almost) every species ever recorded at Gatwick!

The first 20 or so species in our database (sorted by scientific name)

Sussex-based ecologist Graeme Lyons forged the path with this work; again with the SxBRC, he completed the mammoth task of compiling pan-species lists for the entire Sussex Wildlife Trust reserve network (no mean feat with over 10,000 species)! He left this 'master list' as a sort of legacy to Sussex WT, before moving on to pastures new (busy creating lists for other sites I'm sure). 

For comparison, the SxBRC has confirmed around 2,400 species have been recorded to date at Gatwick, but the reality is that I've checked off 1,853 so far in our master pan-species spreadsheet and most records here are only up to 2018... so I'm already 500 species out of date! Once I have cleared this backlog, it will be very interesting to see the rate of new species additions to the airport list each year.  

All species are treated equally, whether abundant or rare, such as a common lichen we might see on the same tree every day, or the one-off sighting of a Leisler's Bat. They are included so long as they are native or naturalised in the wild and have been identified to the species level as accurately as possible (in some cases even via DNA barcoding techniques). 

The brilliance of our list is that it can be filtered and sorted any which way.

From  A ...

Abax parallelepipedus -  a type of Carabid (ground) beetle

To  Z ....

Zygiella x-notata

Missing Sector Orb Weaver © Graeme Lyons

From our earliest official species record at Gatwick in April 1962...

Skylark Alauda arvensis (RSPB)

To our latest new species (which would very much like to snack on our earliest) in October 2020.

Merlin Falco columbarius (RSPB)

Gatwick's pan-species list is the result of a huge group effort, with the biological records dating back to the 1960's and contributed to by a large community of wildlife professionals and enthusiasts. The master spreadsheet comprises several columns, such as the year a species was first recorded, the year it was most recently seen, an example of the location, plus any conservation designations it might have.

The earliest 15 or so species to be recorded at Gatwick were plants, birds, dragonflies 

and a scavenging beetle from an old Knacker's Yard

This helps me to identify gaps in the database (of common or rare species we might have overlooked), as well as the things which might have disappeared, or most recently arrived. Just by searching for a key species, I see it is missing from the list, so there's more recent invertebrate data still to incorporate, along with historic data from previous ecology reports (some of which are being scanned and entered manually by SxBRC).

A few of the benefits of keeping a pan-species master spreadsheet for the airport:

• Pulling together old and new information for every single species, such as when it was first recorded, when it was last recorded, the sites on which it has occurred, any conservation designations it has or previously had and a precise location where it might be found.

• Filtering by conservation designation helps us to identify our most rare and vulnerable species - below I can see that 25 of our moths have some sort of status for their conservation, but I also see that we have only entered moth records up to 2018, so there are probably more to add.

• Gaps in our monitoring: 300 species of fungi demonstrates a high recording effort (mostly all down to Nick Aplin of Sussex Fungi Group!), but 11 species of lichen is not much and we haven't a single species record for algae.

• Species lost: 6 bird species haven’t been recorded since 1997, at least 4 of which had previously been breeding here. By cross-checking with the bird conservation organisations, we can see these particular species have been declining nationally.  

• Identifying useful surveys: at least 138 invertebrate species were picked up from the water quality monitoring reports by a third-party consultant, regularly undertaken since 2011. 

• Data flow issues: by sending copies of our list to individual wildlife recording schemes, they can indicate where they are waiting on relevant data from us.

• Highlighting importance of partnership work: without the huge database of records collected and centralised by the Sussex Biodiversity Record Centre, a comprehensive list would not be possible. They ensure that the wider data is kept safe, reaching the relevant wildlife recording schemes and conservation organisations.  

Many thanks again to Lois, Clare, Bob and all the staff and volunteers at the Sussex Biodiversity Record Centre for your help and feedback. Also a huge thank you to everyone who submits wildlife records - every little helps and over the years the understanding of our habitats gets better and better.