Showing posts with label charts. Show all posts
Showing posts with label charts. Show all posts

6 October 2019

Summer bird report: a summary and some stats

Hello! Hello! Is this thing on?... The following is an update of key birds and stats from June-end-of-August on the patch (a very similar update to below also appears in the Wren Wildlife and Conservation Group newsletter) 


Early summer and breeding bird update
A summer bird report would be very lean indeed if it was not for the fact that the traditional ‘summer’ month of August happens to coincide with the beginning of Autumn migration for birds.


So this is really a report in two halves and we will start with the true summer months of June and July before we get into the early stages of Autumn migration.


It has been a mixed year for our breeding birds. We know that Lesser Whitethroat bred around Long Wood, but think we only had three territories due, most likely, to loss of habitat. There were a few concentrated areas of the patch where there seemed to be a lot of young Common Whitethroat with our first newly fledged birds on 5 June. Chiffchaff territories appear to be down on normal and Willow Warbler almost certainly didn’t breed locally this year.


Reed Warbler showings were strong with a pair on the Roding (5 June) and two singing birds on the Shoulder of Mutton.


Our Meadow Pipits were seen carrying food on 9 June in Brooms, but this species still seems to be hanging on by a thread as a breeding species; we had four territories earlier in the year. Similarly, our iconic Skylark - although still singing - did not display any evidence of having bred successfully this year.


Little Owls have been seen on numerous occasions, although we are not sure whether they have bred successfully this year and we sadly also found a predated corpse. Our small colony of House Martin were seen over their usual colony on Aldersbrook Estate and up to 33 birds were seen by the end of the breeding season with around 12 birds staying on into September after the main departure. 

Little Owl - N Croft

Great Crested Grebe bred on Perch Pond but sadly we don’t believe any of the chicks made it to fledging. 


House Sparrows seem to be doing very well in the small number of colonies in the area with over 100 birds seen around Jubilee. Goldfinch and Greenfinch numbers both broke records this year; interestingly, they may actually be beneficiaries of the new growth in the fire-damaged parts of the Flats. But Reed Bunting, like Willow Warbler, sadly seem to have been lost as a breeding species (whether permanently or temporarily, only time will tell).


A Common Tern was seen on 8 June (400 metres East of Wanstead Park). But first on Patch (taking it strictly by the birders’ definition) was a month later with a very obliging bird that perched up for Nick C on Shoulder of Mutton on 8 July and probably the same bird seen fishing on the Basin the following day. Nick also saw a young bird later in August. Several of us have missed C Tern for the year.

Common Tern - N Croft

We had at least two different Yellow-legged Gulls at slightly different stages of maturity and present on numerous days, normally to be found loafing with the other large gulls on the pitches. The first one to appear was on 8 July.


Yellow-legged Gull - T Brown

The first returning Black-headed Gull, and indeed first juvenile gull of the season, was seen on 1 July. For those impressed by juvenile gull plumages, we think Black-headed Gull youngsters are among the most pleasing to the eye. My second favourite juvenile gull is the Lesser Black-backed Gull and we got some of these lovely dark chocolate birds back on 19 July. 


Juv Black-headed Gull - J Heal



The first returning Common Gulls always arrive later than the Black-headed Gulls, and we got the first ones back on 15 July, with numbers only really picking up later in the autumn. Later in the season Nick also picked up a lovely juvenile Mediterranean Gull on Heronry that almost caused a twitch before it flew off (first for the year) on 30 August.


Hobby seemed to have a successful year on the Patch and we believe that two birds fledged successful from the breeding pair that were seen frequently through the summer (one of which I was thrilled to add to my garden list in Leytonstone).


Bullfinch have been seen on several occasions around the Old Sewage Works with four birds seen on 11 June, although they were very difficult to pin down and I seem to be going through a second year in a row without seeing or hearing any.


Our first Common Sandpiper for the year appeared on Alex on 27 July - found by Tony B with  a Green Sandpiper found by Rob S on Heronry on the 14th August. 


August and Autumn Migration
August happened with a bang. Most (but not all) of the birders stopped taking pictures of invertebrates and raised their eyes to tree tops and skies again as migration began. In fact, this year autumn migration seemed to take off properly on 11 August. Chart 1 shows some of our core passage migratory bird sightings stacked up across August reaching a zenith on 29 August when we had 12 Wheatear, seven Common Redstart, and six Whinchat amongst other things.

Chart 1: Total sightings



The Spring had been dreadful for Willow Warbler and we did not seem to have any sticking around as regular singers (as already mentioned), but the passage migrating birds started to appear from the first day of August. In fact, Willow Warbler were seen on 21 of the days in August with individual bird high counts of seven on four separate days.


The 1 August also produced our first Garden Warbler since 25 June (a pretty narrow gap between ‘end of Spring’ and ‘beginning of August’, I am sure you will note, and one which most likely reflects outlier birds).


And if Swallows make a summer, then surely their departure marks the end of summer? If so, we started seeing southward-bound birds on the move from 2 August (although the major flow may well not have started yet). We don’t have breeding Swallows anymore, but even the numbers of passage birds seen were down by around 60%.


Our shortest staying summer breeders are, of course, Swift. Checking my own records, they were a constant feature this summer from 6 May until 3 August. On the weekend of 3 / 4 August, they were screaming around above my house and parts of the patch. The following weekend, like Keyser Soze (I’m afraid you either get this 90’s film reference, or you don’t), they were gone. Actually, ‘gone’ may not be strictly correct as we have still been picking up passage birds moving through, and the last ones seen were only a day off our ‘latest’ record and watched by Nick C from the Old Sewage Works on 1 September. Although the number of days these birds were seen were normal, we believe the numbers of resident breeders were down by up to 70% on previous years.


For the first year ever, we recorded Wood Warbler in both Spring and ‘Autumn’, both in a similar location in Long Wood, with the Autumn bird found by Nick on 7 August. We believe this was the first Wood Warbler recorded in the Autumn across London.

Wood Warbler - N Croft

Amongst a set of core passage birds (Tree Pipit, Wheatear, Whinchat, Common Redstart, Spotted Flycatcher, Pied Flycatcher, and Yellow Wagtail), Wheatear, as usual, kicked things off with the first returning Autumn bird on 8 August found by Nick C. Since then numbers have mostly been lower than usual. The peak day on 29 August with 12 birds was exceptional as the second most productive day this August saw three.


As already mentioned, 11 August felt like the day that Autumn Migration really started; Tony B found Pied Flycatcher in Motorcycle Wood in the SSSI which only Bob V was quick enough to twitch successfully. But the rest of us need not have worried. There were to be plenty to go around. 2018 was the only year in my five years of birding locally that Pied Flycatcher failed to feature on my year list, so I was extra keen to secure one this year. Luckily, it turned out to be a record year for them. Pied Flycatchers were recorded on each day from 23 until the end of August, with the 24 August seeing a total of six birds; doubling our previous day record.

Pied Flycatcher - J Heal

Spotted Flycatcher are often the dead certs of the Autumn migration period, but, unlike their slightly scarcer pied cousins, 2019 hasn’t been fabulous for them. Nevertheless, this species was recorded on 16 out of the 21 last days of August with a peak of five birds on 27 August.

Spotted Flycatcher - J Heal

The first Autumn Whinchat appeared on 16 August, and, since then, were recorded every single day through the rest of the month with a high-count of ten birds on 27 August.


Whinchat - J Heal

It was a record-breaking season for Tree Pipit. Last year I had the only Tree Pipit of the Autumn; a single bird calling low over my head near Long Wood. This year we had a short but tremendous run of sightings, also with record numbers of birds and mostly seen perching, sometimes circling, and flying up and down from ground to tree. From the first sighting on 11th August until the end of the month, there were actually only three days when Tree Pipit were not seen at all, and we have had up to six birds in a day.


The passage migrant that has been most disappointing is Yellow Wagtail; normally one of our strongest performers with double figures of fly-overs common in the Autumn days. Indeed, partly due to the poor run, and more probably because young family duties mean I don’t get out early in the morning very often, I have actually missed this species altogether on the patch this year. And so now is a good time to study ‘Chart 2’ which shows just how low the numbers of Yellow Wagtail have been compared to last year. 2018 and 2019 is perhaps not a fair comparison as our most devoted patch watcher was around a lot less last year, so I have tried to iron this inconsistency out by plotting the average number of birds seen divided by the number of days the patch was actually watched. This shows both how good 2019 has been overall, but how poor it was for Yellow Wagtail.

Chart 2: 2018 and 2019 comparisons

To plot a year-on-year comparison slightly differently, ‘Chart 3’ shows the total number of core passage migrant birds recorded per day with Yellow Wagtail removed (so, Pied Flycatcher, Spotted Flycatcher, Tree Pipit, Whinchat, Redstart, Wheatear). Some of the long flat red lines for 2018 show some of the days when nobody was out recording, but the relative size of the peaks compared to blue 2019, again shows what a good year it has been.


Chart 3: Totals compared for 2018 and 2019

This now leads me to make another conclusion, not about the year, but about the location. On 29 August, Wanstead Flats had double the number of Spotted Flycatcher of any other site in the London Recording area, it had 50% more Pied Flycatcher than any other location, 12 times as many Wheatear, seven times as many Common Redstart, and 50% more Whinchat. The 29 August may have been a good day for Wanstead Flats, but we had more of those migrant species on our first, second, and third best days than any other London site had on their best day. Wanstead Flats surely remains the pre-eminent location for passage passerine migration in London which is just one of many reasons why holding a summer music festival on this site is such a poorly considered idea. 


Other August birds of note included a pair of fly-over Greenshank on Wednesday 14th from Nick C. Nick was one of a very select few who had ever seen Greenshank from the patch. That was soon to change quite dramatically, but that is a story for September and will be in the next Newsletter.


On a number of days through August, from 14th onwards, a female Mandarin was present on both Jubilee and Heronry (we are assuming it is the same bird).The first returning Water Rail for the Autumn appeared in Wanstead Park on 25th August. A Great [White] Egret flew over the Wanstead Flats on 27th August.

Female Mandarin - N Croft



Tantaslingly, there are always the ‘ones that get away’, such as a possible Nightingale on 21st August on the Flats, but that’s birding for you!

25 February 2018

Lapwing by numbers

Updated blog post...

As the cold-weather front known as the 'Beast from the East' has finally ended, almost a week after it first started to chill the country, it is worth reflecting on impact on bird movements and behaviours. On the Patch we've had a frozen Dunlin, a pair of Golden Plover, several Snipe and Woodcock showing uncommonly well, and big thrush movements. But most impressive has been the number Lapwing that passed over.

In six days we had just over 1600 individual Lapwing pass over, with a low of 91 birds counted on Tuesday and high which more than doubled the previous Patch record and saw 860 Lapwing fly over on Wednesday. These huge numbers belie the fact that Lapwing are good birds for the Patch.

One of the birds from yesterday (24th February 2018), flying over Police Scrape

'How good?' I hear you ask. Well, I have been doing some rather unscientific number crunching. The source for my data was our collective Twitter feeds: counting up every time Lapwing were reported since Jono started all of this back in the dark age of 2009 (probably before I had even heard of Wanstead Flats to be honest).

What I discovered was that Lapwing were not quite as scarce locally as I had thought. Since the first Twitter record in December 2009, there have been 62 days when Lapwing were recorded on the Patch and a huge total of 3002 individual birds have been seen. Of this large total, the vast majority have been seen on just eight days, over half were seen in the last week, and 29 per cent of the total were seen on Wednesday!

Each of the eight days when Lapwing have been most frequently seen have been, unsurprisingly, unseasonably cold, averaging out at 8 degrees celsius colder than the monthly average (yes, I really did go back and check the local weather reports for each of those days - I'm not just making this up).

If we break the data down a little further, the spread by month of sightings and numbers of individual birds is also interesting (well, it is to me anyway). I have collected these data into a double 'y' axis chart below.




Looking at the red columns corresponding to the right 'y' axis, we can see the total days by month that Lapwing have been seen. October is the month we seem to be most likely to spot a Lapwing with over a quarter of all sightings falling in this month. This is followed closely by February with 12 days. January and December take joint third place. 

If we switch to the blue line and the left 'y' axis, this shows the number of individual birds seen by month. Then February blows every other month out of the water. It stood out before the last week, but now is on a different level: 2080 birds have been seen which is almost 70 per cent of the total and is an average of 173 birds per day that Lapwing were recorded.

I'm not sure I want or need to try and draw many conclusions from this collection of data, but it hopefully gives us a slightly clearer picture of the Lapwing movements from this one geographical location.