Countless, cloud-like swarms of martins and swallows swoop, turn and dive and over dark waters. The local sparrow hawk glides silently overhead, checking out her chances amongst the dancing flock. corvids squabble and scuffle over the best perches, while pied and grey wagtails march at ground level, in a seemingly never-ending hunt for insects. What an idyllic spot for a spot of bird watching...
...at our local sewage works!
prime spot! |
Here in Warwick, there are very few sites for quality birding and even fewer with contained, still water to attract wildlife. So, the water treatment plant on the Stratford Road has become one of the team's regular locations to visit, to attempt to spot potential additions to our list. It appears we are not the only ones to hold our noses in hope.
Bird species seen across UK sewage works make for impressive reading over the years - dipper, glossy ibis, breeding green sandpipers and Siberian chiffchaff to name a few. Beckton Sewage treatment works, East London, has clocked up 148 species including curlew, dunlin and Caspian gull, along with records of grass snakes and bank voles. Northumbrian Water have planted reed beds at Birtley water treatment plant, attracting bittern, gadwall and jack snipe. A 'Waste to Warblers' tour of the site was even offered back in 2016. Swindon, Salford and Bicester have all also turned their sites into mini nature reserves to balance human need with protecting biodiversity. Brilliant!
So, why do these manmade and rather smelly locations draw so many birds? Well, the percolating filter beds in sewage treatment works have high macroinvertebrate densities, don't you know... (in other words, the water is full of oxygen and nutrients, so has lots of bugs in it that are big enough to see with the naked eye). Fly larvae hatches, providing aerial food for birds (and bats, according to other studies) and providing plenty of opportunity for a healthy food chain. As Tom Stephenson, US birder and author, puts it so concisely, 'Water, heat and fertilizer...what more could you ask for?'
Breakfast for hirundines...? |
Lizzy