How did winter mortality, poor migrant return, and difficult breeding conditions affect the species we saw in 2018? Not as you might think, writes Roger Emmens
What we saw in 2018
2018 was a strange year.
The ‘Beast from the East’ froze our resident birds and knocked the populations of the more susceptible species back. Then stormy weather in the Mediterranean and North Africa badly affected many spring migrants, resulting in a reduced and delayed migration season and start to breeding. Finally, the long, hot, dry summer made it difficult for many species rearing young, so that breeding productivity was compromised. Autumn migration as a result was a much quieter affair than usual.
The overall effect was that we ringed a lot fewer birds in 2018 than usual. And we were not alone in that: other ringing sites in our region also noted that numbers were well down.
So as the year’s observation data is finally analysed, it is quite a surprise to discover that we’ve actually seen quite a lot. For a start, 138 species have been recorded, which may be a site record – we only have year by year totals since 1980 and this is the most species seen since then.
There were no new species added to the Rye Meads list, but we recorded our second Great White Egret, our second Spoonbill, and our fourth Little Tern. Two Avocets represented only the fourth time of recording.
Altogether, we set new record counts for seven species, and equalled the previous record of a further seven. One of the equalled records was just of a single bird, namely Osprey (the 25th year we’ve recorded a migrant passing through), and another of a pair of Black-necked Grebes (we’ve had a pair visit in five different years, but sadly they didn’t stay to breed this time).
So what are our new species records? We start off with Mute Swan, where the summer non-breeding flock reached 76, setting a new site record for the second year running. It’s not at all clear why the past two years have seen such a build-up, but it’s quite a sight.
The eight Egyptian Geese which flew over in January are more easily explained, with the species steadily increasing in the Lea Valley. The same explanation can also be applied to our record count of 14 Hobbies. Similarly, the new record of four Yellow-legged Gulls came in the ninth year we have recorded this also increasing species.
Our remaining new records all apply to commonly occurring birds at Rye Meads, species that normally we just tick off as ‘present not counted’. And there’s the likely explanation: over the past two winters, we’ve started to count our resident winter birds on the same day as the WeBS counts. For many common species, we’ve never systematically tried to count them, other than by breeding survey of singing males or territories. So we don’t really know how many of them remain on site for the winter, or if there is a wintering influx.
Thus the count of 93 Carrion Crows in February may be typical for all we know, but it remains our record for now. Most of these birds are over the Thames Water works, attracted by pickings at the Grease Tanks (on your left just before the toll barriers as you come down Rye Road from the Roydon end) and also at the tanks towards the rear of the site. This is a species which is clearly more likely to be found on site in larger numbers in winter.
The two remaining record species were Great Tit and Robin, with 53 and 48 respectively. Given that the breeding survey for 2018 found 38 pairs of Great Tit and 33 singing male Robins, it is clear that if counts were made in the summer months, these records would be well beaten; nevertheless it is of interest to see what a winter count can show up, and making such counts on a regular basis year by year will help to show up any wintering population trends in future.
So following these surprising results, let’s go out into the field with renewed enthusiasm in 2019 and see what we can find. We’ve already clocked our 228th species, which predictably came in the form of a Cattle Egret. Will we get another new species this year, and what might it be?
Might it be a wetland specialist like Penduline Tit or Aquatic Warbler? Or perhaps it’s time for other increasing visitors such as Black Kite or White Stork to pay us a visit?
Of course, like football matches, often the unfancied team springs a surprise, so perhaps a trans-Atlantic wanderer, such as a Lesser Yellowlegs or a Broad-billed Sandpiper, or maybe a Ring-billed Duck? Or could we host a classic misdirected migrant, such as a Red-flanked Bluetail or an Alpine Swift?
It’s the lure of such finds that keep us interested!