We took the moth trap when we stayed in Wokingham, Berkshire, last night:
That moment when you realise that you’ve just found your first Buff-tip!
This is a moth that repays study from every angle, a silver birch twig in living form: 
Another surprise in the moth trap was this Stag Beetle. It is sadly unusual to come across Stag Beetles these days, even in areas like this where they were common 20 years ago:
The numbers of moths in the trap this morning was not great, but a couple of new Prominents caused some excitement. The first was the remarkably-shaped Pale Prominent:
We struggled to make sense of the strange structure on the head of this moth. However, as it warmed up and became more active, more features became visible:
The tall structure between the eyes, that looks almost like a frontal shield, is in fact a pair of vertical labial palps. Pale Prominent moths have distinctively shaped labial palps. They are found either side of the probiscus and together with the much smaller maxillary palps appear to have a role in scent, especially sugar, detection. Below is a graphic showing the more traditional arrangement of palpi (© https://www.britannica.com/animal/lepidopteran/Form-and-function):
Even better was our first Swallow Prominent, a good-sized, beautifully marked moth: 
Lesser Swallow Prominent is a confusion species, but the narrow white wedges (indicated by the arrow) look good for Swallow Prominent to me, although as always with moths, I am happy to be corrected. This is the 120th species of moth we have identified in the last 11 months in our small Headington garden, with the number of new species arriving showing no sign of abating! 
2 Great Skuas found at lunchtime on Saturday had the decency to stay until I could get there at 1:50pm: 
But within 30 seconds of my arrival they took off…
… gained height to the north…
… before returning to the middle of F2, joining the small numbers of Arctic Terns that were present with the local Common Terns:
The Skuas remained on F2 for another 20 minutes, before departing high to the west. Good to bump into George Best at the reservoir too.
As some early spring warmth has arrived, I have begun putting out the moth trap a few times a week in our small suburban garden. This is my first spring trapping after a moth trap arrived for Father’s Day last June (see here for the highlights of last summer’s mothing). As such, nearly everything I catch is new to me, which creates exciting and challenging identification puzzles. Moths have fabulous names. There are Small Quakers, Powered Quakers and Common Drab Moths, but mostly there seem to be a lot of Common Quakers, the default spring moth:
The appropriately named Early Grey always catches the eye:
A personal favourite is the Brindled Beauty…
… not least as it possesses fabulous antennae:
The Muslin Moth may not look that interesting from above:
But this is one magnificent beast. There is something quite noble about that face:
The small but colourful Red-green Carpet. The green colour also extends to it’s eyes: 
A surprise in the trap was this Dark-edged Bee-fly: 
These beasts predate wasp and bee pupae (see here for my experience of Dotted Bee-fly attempting the remarkable process of kicking it’s eggs into bee’s holes on the Oxfordshire downs).
That is one giant proboscis: 
Bring on the warm summer nights and an even greater selection of moths to enjoy.
A recording of the Oxford Iberian Chiffchaff is now on Xeno-Canto [David Darrell-Lambert, XC411346. Accessible at www.xeno-canto.org/411346]:
Mick Cunningham made a comment, here, about the Oxford bird perhaps lacking the “wheeet-wheeet” part of the song typically heard by Iberian Chiffchaff. Now we have a recording and a sonogram from Xeno-Canto, I can hear and see what he means. Firstly, listen to an Iberian Chiffchaff recorded in Spain [Luis Gracia, XC409152. Accessible at www.xeno-canto.org/409152].
From having listened to a dozen recordings from Spain, to my ear there are three parts to a typical Iberian Chiffchaff song, always in this order:
We can see these on the sonogram of the bird recorded in Spain (labelled by me):
The Oxford bird’s sonogram looks like this (again, labelled by me):
To my ear, and from the sonogram, there is no “wheet-wheet” middle part to the song of the Oxford bird. Now, I am no expert on bird song, sonograms or Iberian Chiffchaffs. In fact I actively want this bird to be an Iberian Chifchaff for deeply held personal reasons: I have not seen one in Oxfordshire before. But I have not found a recording on Xeno-canto of Iberian Chiffchaff from Spain that does not have at least one “wheet-wheet” in the middle section. Admittedly, I have not listened to all the recordings, I have a family to keep happy and full time job. But somebody out there with more time and expertise must be able to help!
To my mind, this leaves four possible options:
You decide! Thanks again to Mick Cunningham for noticing this feature.
The excitement of seeing Oxfordshire’s second Iberian Chiffchaff on Monday evening was tempered by two things: firstly, it was cold and windy, so the bird was rather secretive and the light was terrible; secondly, by the fact that whilst the bird was producing lots of classic Iberian Chiffchaff song, up to half of the song that we (Dave Lowe, Andy Last, Ian Reid and myself) heard that evening from this bird appeared to be similar to that of Common Chiffchaff. This raised the question in my mind of whether this bird could be a mixed singer?
Iberian Chiffchaff, unlike Common Chiffchaff, has different advertising and conflict songs:
“In the context of spring vagrancy, Iberian Chiffchaff has two major song types: an advertising song used by males trying to attract a mate and a conflict song used primarily during antagonistic interactions with other males. The same is true of Common Chiffchaff, although in that species the advertising and conflict songs are virtually identical. The conflict song of Iberian is very similar to that of Common but the advertising song is more variable and contains song elements not used by Common Chiffchaff“. (Collinson and Melling 2008)
I trawled through Xeno Canto to try to find some examples of both the conflict and advertising songs of Iberian Chiffchaff.
Iberian Chiffchaff advertising song from Iberia. [Luis Gracia, XC409152. Accessible at www.xeno-canto.org/409152] This is the well known song of Iberian Chiffchaff:
Possible Iberian Chiffchaff conflict song from Iberia. [Paulo Alves, XC304478. Accessible at www.xeno-canto.org/304478]. Similar, but not identical to, the song of Common Chiffchaff:
Common Chiffchaff, from the UK. [Frank Lambert, XC324041. Accessible at www.xeno-canto.org/324041]. Advertising and conflict songs are identical in Common Chiffchaff:
Collinson and Melling state that “the definition of a ‘mixed singer’ is reserved for those birds that use song elements characteristic of both Iberian and Common Chiffchaff within a single advertising song“. This was not something that we heard on Monday evening. The Iberian Chiffchaff was either in full “Iberian mode” or reverted to a song similar to Common Chiffchaff. Bearing in mind the above, this was probably Iberian Chiffchaff conflict song. Once again, an instructive experience with a great bird, though it would be interesting to see someone address this issue properly with sonograms taken from recordings of this bird.
This is turning into a good spring for Black-necked Grebe in Oxfordshire. The latest to be found was a summer plumaged bird on the small Grimsbury Reservoir in Banbury. I popped in at lunchtime today…
Just a few meters offshore, in full summer plumage… wow!
These were the sort of views of Black-necked Grebe that I had only previously dreamt about. Look at those eyes!
Those golden ear tufts!
Occasionally the bird would tilt it’s head to scrutinise birds flying over:
Good to bump into Ewan and Moth there too. There are more details about Black-necked Grebe records in Oxfordshire in this post here.
This is an article that I wrote for the Oxon Birding website, as part of the March 2018 bird news update:
Black-necked Grebe is a scarce passage and winter visitor to Oxfordshire but has been recorded in every month of the year and in every year during this period, except for 2008, when there were no records in the county. Scanning a reservoir or gravel pit in spring and finding a summer-plumaged Black-necked Grebe may be the highlight of spring migration for birders in a land-locked county such as Oxfordshire. This article looks at the pattern of occurrence for Black-necked Grebe in the 14 years from 2000 to 2013 inclusive.
As many observers can submit records for each individual bird present, using the total number of records per year on the OOS database does not provide an accurate reflection of the actual number of birds present. The table below was calculated by examining the OOS reports from 2000-2013 and determining the likely number of birds present in each month, rather than the total of submitted observer records. A conservative approach to numbers was taken if birds were reported from nearby locations on consecutive dates, so the real numbers of birds involved may well be higher than this estimate. Figure 1 shows, for example, that there has been a total of 5 Black-necked Grebes recorded in the month January in the years 2000-2013:
Spring records:
There is a clear spike in records beginning in March and increasing in April. These records are of wintering birds returning to their breeding grounds in northern and central England. Black-necked Grebes were recorded in the month of March in three years and in the month of April in six years during the fourteen-year period between 2000 and 2013. There were cumulative totals of 9 birds recorded in March and 18 in April (see figure 1). Birds recorded in early March, such as the birds pictured below at Dix Pit on 7th March 2018, are in predominantly winter plumage. By the end of April most Black-necked Grebes will be in full breeding plumage.
However, the totals for March and April are inflated by two significant flocks of Black-necked Grebes: 5 birds together at Dix Pit on 6th March 2002 and 7 summer plumaged birds together at Farmoor Reservoir on 27th April 2012. Some of these birds remained for a number of days and gave fabulous views, even performing courtship displays on occasions:
Breeding season records:
There is only one May record (of two birds on 24th May 2013 at Farmoor) and a single record from June: a bird in full breeding plumage seen at Standlake on 4th June 2000. This is the only June record of Black-necked Grebe in Oxfordshire (OOS Annual Report, 2000) and at time of year when breeding birds are usually on territory, hence the paucity of Oxfordshire records in early summer. This bird could have been a very early failed breeder, but perhaps is more likely to have been a breeding bird dispersing in search of potential nesting habitat. This species is noted for “widespread aerial reconnaissance” (CBWP).
Post-breeding records:
The gradual increase in records from July through to September correlates with the arrival of failed breeders and post-breeding dispersal. Failed breeders may leave breeding ponds as early as July, whilst post-breeding dispersal typically occurs from mid-August (Migration Atlas, BTO). This accounts for the gradual rise in Oxfordshire records in the autumn period. In eight of the fourteen years analysed Black-necked Grebes were recorded in September, making this the most productive month overall for records in Oxfordshire, even though the overall number of birds found in September, sixteen, is eclipsed by the total found in April, eighteen.
Winter records:
In the western palearctic Black-necked Grebes winter within the breeding range, with movements to the coast when inland water-bodies freeze. CBWP states that most birds are on their wintering grounds by November and that the UK wintering population may receive birds from continental Europe that shelter in the estuaries and inland water bodies of south-east England. Winter records in Oxfordshire increase from October to December (see figure 1) and could conceivably be from both Black-necked Grebes that breed in the UK or from birds that have migrated to southern England from breeding grounds in continental Europe.
A global footnote:
The movements described above are trivial compared to the migration of Black-necked Grebe in other parts of its global range. Hundreds of thousands of Black-necked Grebes are thought to winter in the south Caspian Sea off the coast of Iran, with tens of thousands on Turkish lakes in winter (BTO, Migration Atlas).
In North America nearly 1.5 million Eared Grebes (the name by which Black-necked Grebes are known in the west) migrate to Lake Mono in California where the adults undergo a complete moult and the juvenile birds a partial moult. The birds at Lake Mono more than double their weight on their autumn staging grounds, their chest muscles shrink as their bodies favour rapid fat deposition. Eared Grebes are rendered flightless during this period and are flightless for up to 9 or 10 months of the year, the longest flightless periods for any species bird capable of flight in the world (Cornell 2017). Eventually the brine shrimp population, on which the vast numbers of grebes feed, collapses. The grebes, by now having completed their moult, migrate to the coast at night. The nocturnal movements of so many birds can leave them prone to severe weather-related incidents, such as this report of some 4,000 Eared Grebes that landed in a Walmart car park in a storm in Utah in December 2011. In Europe both diurnal and nocturnal migration of Black-necked Grebe has been recorded, in contrast to the purely nocturnal migration of Eared Grebe in North America (Migration Atlas, BTO).
References:
“Bird Atlas 2007-2011”, BTO, 2013.
“The Birds of the Western Palearctic”, concise edition (CWBP); Snow & Perrins; OUP 1998.
“The Migration Atlas”, BTO, 2002.
The Cornell Lab of Ornithology; “Eared Grebe” website; 2017; [https://www.allaboutbirds.org/guide/Eared_Grebe/overview]
Weblinks to news items on the mass downing of thousands of Eared Grebes in Utah in 2011:
https://www.ksl.com/?sid=18498424
https://www.cbsnews.com/news/more-than-4000-birds-crash-land-in-parking-lot/
On 6th March 2002 I found a flock of 5 Black-necked Grebes a Dix Pit, one of my first noteworthy self-found birds in the county. A photo of that flock, by George Reszeter, was published in Birdwatching magazine. Despite the caption on the photo, I don’t think it is too unusual it is to see small groups of these grebes, as recently a party of 5 have spent the last couple of months at Sonning Eye gravel pits.
Black-necked Grebes appear annually in Oxfordshire, often in small numbers in early spring, as they move to their breeding grounds on pools in northern England. I thought of the flock that I found in 2002 as I headed out to Dix Pit this morning, 16 years and one day later. It was a nice moment then, when scanning from one end of the pit, I picked out 2 Black-necked Grebes on the far side. I worked my way around the gravel pit to get closer, the light was better and the birds showed nicely. These birds were more in winter plumage than summer. Their heads and necks are taking on the black of their breeding plumage, but they had not yet grown their fabulous golden ear tufts. Nevertheless, seeing the red eye is always a treat:
Having found a single, very distant, Black-necked Grebe on Monday at Henley Road gravel pits, it was good to get much better views of these beautiful grebes:
A productive couple of hours on the southern border of Oxfordshire. The redhead Smew was not only on the same pit as when I lasted visited on 7th February, but was pulled out of the water on exactly the same branch, above.
The Smew was here:
The other side of the peninsular produced a distant Black-necked Grebe. It was mobile and fishing constantly:
I wondered if this bird may have been part of the flock of 5 Black-necked Grebes that had spent the last couple of months on nearby Sonning Eye gravel pits, so I popped over to have a look.
As well as all the usual suspects, such as Great Crested Grebe, above…
Sonning held 3 Goosander (above), a Little Egret, a singing Cetti’s Warbler, a flock of 30 Siskin and 18 Goldeneye. I could find no sign of the Black-necked Grebes in the small bay past the sailing club, perhaps they have moved on?
The male Goldeneye were displaying, bobbing their heads up and down, whilst their evocative calls sounded out over the lake, something like this:
