In 2004, with one young son and another on the way, my family and I relocated to our present home on the Dengie peninsula, a thinly populated but commutable place halfway up the coast of Essex. Our two human fledglings, and the work needed to support them, took absolute priority. So out went the twitching (but not before the 400-species milestone had been reached, on the eve of our elder’s first birthday) and in came a focus on meaningful local birding. This has since involved the regular monthly WeBS count on the Blackwater Estuary and associated breeding bird census, a BBS square, the Heronries Census, several tetrads for the 2007–11 Atlas, an annual forest survey and annual monitoring of local sites for Rare Breeding Birds Panel species. Sadly, there has been no BB rarity (yet), but the birding has been highly satisfying, and I’ve had a strong sense that the ebbs and flows of local bird populations are well covered. Or so I thought.
The national lockdown from March 2020 had an initial chilling effect on birdwatching activity. Within a few weeks, however, the UK Government had slightly widened the limits of permitted daily exercise in England. As long as social distancing was strictly observed, it was permitted to drive to one’s exercise location, if the exercise lasted significantly longer than the drive, and it was also permitted to exercise more than once a day. With my commute to London now replaced by a working day at home of endless Zoom meetings, pretty much from 8 am to 8 pm, this opened the door for pre-breakfast or evening birdwatching walks in the local area – essential for my own mental health at a time of crisis, but also coinciding with the breeding season. As monitoring breeding birds is my top birding passion, the scene was therefore set for something not previously attempted: a local breeding bird census.
With both virus control and ornithological knowledge in mind, the sensible objective was to define a census area that was unlikely to be visited by a similar observer; was representative of local habitats; and which could be reached in little over five minutes by car. I chose an area of 62 km² of the western Dengie peninsula, amounting to 1.69% (or 1/59th) of the land area of Essex – potentially significant enough to gather meaningful data as well as to draw some wider conclusions.
For historical reasons to do with seasonal marshiness in medieval times, this area is not blessed with many public rights of way. It is also now a mainly open landscape. To survey the area, I would need to walk every right of way and observe from every public road, at least once during the breeding season (in calm and dry weather), while counting apparent pairs or territories of a range of target species, whether visible or audible. For the more conspicuous species, this enabled an almost certainly complete census to be undertaken – not only of, for example, wildfowl, waders and raptors, but also of warblers, many species of which sing almost constantly at the survey times. The target species were essentially all but the commonest passerines, whose counting would not have been feasible in the time available.
The crepuscular opportunities also allowed something not previously attempted, even during the Atlas periods: an owl census. My night-time excursions for ‘owling’ coincided perfectly with the rest of the family watching the entire box set of Peaky Blinders, prompting discussions among us as to whose activities were actually the darker. This owling led to some major surprises – including the discovery of a previously unknown population of Long-eared Owls Asio otus. This goes to show that, even when you’ve lived somewhere for 16 years and prided yourself on local birding, you never know as much about the local bird populations as you thought you did. There is always something to find out and boundaries of knowledge to push – right under your nose.
The survey area included sections of two estuaries, the Blackwater and the Crouch. Away from the estuaries, the habitat is open and predominantly arable, dominated by a typical rotation of cereals, oilseed rape and beans, although recent years have seen an increase in land supporting horses (‘equiculture’) or devoted to viticulture. There is little woodland, the largest wood being only 21 ha, although there are numerous small copses and plantations across the area.
The numbers of apparently breeding pairs/occupied territories located for each target species are set out in table 1. For most species, it’s likely that the number given is close to the actual number present. For those with a single asterisk (*), however, the number given is likely to be slightly below the actual number present. And for those with a double asterisk (**), it is likely to be significantly below the actual number – for example because the species is widespread and many birds will have been inaudible or invisible from public rights of way. For those species with numbers in blue, there is strong evidence that the population has increased since the 2007–11 Atlas period, while for those with numbers in red, there is strong evidence of a decline. For those not highlighted, the evidence is not strong either way.
Table 1. The numbers of apparently breeding pairs/occupied territories located for target species in the West Dengie study area, 2020. For the key, see main text.
Great Spotted Woodpecker
These results showed that, even in the short time since the 2007–11 Atlas, there has been considerable change. Seven species have been gained: Cattle Egret Bubulcus ibis, Little Egret Egretta garzetta, Marsh Harrier Circus aeruginosus, Common Raven Corvus corax, Coal Tit Periparus ater, Cetti’s Warbler Cettia cetti and Eurasian Nuthatch Sitta europaea. Nine have been lost: Shoveler Spatula clypeata, Avocet Recurvirostra avosetta, Mediterranean Gull Ichthyaetus melanocephalus, Lesser Black-backed Gull Larus fuscus, Common Tern Sterna hirundo, Lesser Spotted Woodpecker Dryobates minor, Garden Warbler Sylvia borin, Spotted Flycatcher Muscicapa striata and Meadow Pipit Anthus pratensis. Ten other target species have gone up, and 16 gone down. Furthermore, 11 regularly nesting Essex species remained absent throughout: Great Crested Grebe Podiceps cristatus, Little Ringed Plover Charadrius dubius, Little Tern Sternula albifrons, Great Cormorant Phalacrocorax carbo, Common Kingfisher Alcedo atthis, Marsh Tit Poecile palustris, Bearded Tit Panurus biarmicus, Sand Martin Riparia riparia, Grasshopper Warbler Locustella naevia, Common Nightingale Luscinia megarhynchos and Black Redstart Phoenicurus ochruros. Lack of habitat is the explanation for most of these absences. But this cannot be said for Common Nightingale, whose absence is baffling and which has substantial populations immediately outside the area, forming a highly clustered distribution.
Particular highlights from the survey would have to include the two pairs of Cattle Egrets which fledged one young in a Little Egret colony – one of three sites in Essex in 2020 for this colonist, which first bred in the county in 2019 – and the pair of Common Ravens that fledged two young, which may be the first breeding in coastal Essex since the nineteenth century. The Ravens were first detected during an NHS lockdown clap, when one casually flew down the road at rooftop height over our heads, which was surreal. It was also pleasing, and unexpected, to find both Coal Tit and Eurasian Nuthatch breeding in this unpromising environment – both apparently colonists also. Also unexpected was that Common Buzzard Buteo buteo, another recent colonist, had overtaken Common Kestrel Falco tinnunculus as the commonest raptor (just) and that Stock Dove Columba oenas was actually more numerous than Collared Dove Streptopelia decaocto – even though it might seem the opposite given the latter’s preference for human environments.
More negatively, Grey Partridge Perdix perdix, Northern Lapwing Vanellus vanellus, Common Redshank Tringa totanus and Willow Warbler Phylloscopus trochilus were found to be teetering on the edge, and Eurasian Sparrowhawk Accipiter nisus numbers were lower than expected. The extinction of Meadow Pipit was a genuine shock. And just two Turtle Dove Streptopelia turtur territories were found; in both cases the singing males appearing unmated. The Dengie peninsula was until recently a national stronghold for this species, so these birds’ songs seemed to have a particularly mournful and poignant tone this year – very sad.
Owls were a particular highlight. The 11 pairs of Barn Owl Tyto alba and nine of Little Owl Athene noctua were as expected, since these are relatively conspicuous (the former making use of nestboxes put up for them). But the ten pairs of Tawny Owl Strix aluco were a complete surprise, since I had previously encountered the species locally on only a handful of occasions, and had presumed (based on the previous Atlases) that the area was too marginal for it. I had, however, specifically looked for Long-eared Owl in a few places during the previous Atlas, albeit without success. It was therefore a revelation to find six pairs of these, highly significant in an Essex context.
The county population of Long-eared Owl was estimated at around 8–12 pairs during the previous Atlas. It seems, though, that we may not have been looking in the right places: none of the Dengie pairs were in places that were otherwise attractive for birdwatchers. Five of the six (mainly small and dense) nesting woods had adjacent grassland used for equiculture, either for grazing or for cropping. And all six woods had surrounding smaller fields with mature hedgerows – reflecting the species’ need for close cover (in contrast to Short-eared Owl Asio flammeus). These findings suggest that breeding Long-eared Owls may have been overlooked more than previously appreciated. Considering that breeding density is affected by the fluctuating abundance of rodents, it’s tempting to suggest that the breeding population in Essex may in fact be between 20 and 50 pairs, significantly higher than previously assumed.
Importantly, by doing this survey on an area basis, some insights were gained which would not have been possible from a solely site-based survey. For example, the long-standing Common Swift Apus apus colony in Latchingdon church, only a few metres from home, turned out to be the only colony in the area. House Martins Delichon urbicum were found to have switched significantly from farmhouses to houses built since 2015 (linked, it would seem, to planning policies which favour gables suitable for this species). Both Sedge Warbler Acrocephalus schoenobaenus and Reed Bunting Emberiza schoeniclushad retreated to just one site, Lawling Creek, although the census there had shown an increase for both. And Corn Buntings E. calandra were found in four semi-colonial sites, a loss of two sites since the last Atlas – yet at the Lawling Creek census site numbers had increased 20% during that period. For these species, my site-based census at Lawling Creek had been giving a misleading impression of the species’ true status in the area.
The upshot was that this survey was both hugely enjoyable and valuable. In addition to revealing the true status of a variety of breeding birds, it showed that there are benefits to studying at an area, rather than just site, level. Doing this appears to reduce potential observer biases, by ensuring that all habitat types and sites are covered. It also enables some broader phenomena to be identified, such as the highly clustered breeding concentrations of some species. I’m looking forward to following up in 2021 already…
A fuller write-up of the survey, also covering migrants and other wildlife, is scheduled for publication in the 2020 Essex Bird Report www.ebws.org.uk/publications/essex-bird-reports’