• Vincent

The technical year report on the ringing activities in Meijendel, Zuid-Holland, the Netherlands in 2020 has been published!

The report (in Dutch) can be downloaded here or by double clicking the cover image (pdf; 4MB).

An English summary can be found both in this blog post and in the report itself. A series of photos has also been added below.


For the bird ringing activities in Meijendel, Wassenaar, Zuid-Holland, the Netherlands, 2020 was a good year with a couple of surprises. It is superfluous to mention that the corona crisis held the world in its grip. Fortunately everyone in the group stayed healthy. There was a restriction on the number of people allowed to ring at the same time for most of the year and all of our excursions and lectures were of course cancelled, but these were just minor nuisances and otherwise there was little effect on our activities. During 90 days and approximately 530 hours, during all months save January, we ringed 6,616 birds and re-trapped an additional 1,266 (14% out of the total number). During the year we passed the 100,000 mark of birds being ringed since the turn of the century. At the end of 2020, the tally stood at 104,773. Birds were ringed for the following projects:

1) Breeding bird study Constant Effort Sites (CES);

2) Spring migration, dispersion and autumn migration;

3) Genetic studies on Lesser Whitethroat and Chiffchaff taxa;

4) A zoonoses study (pathogens that can be transferred from animals to humans), for which we took blood samples, throat and cloaca swabs and trapped mosquitos;

5) Re-trapping Adults for Survival (RAS) Sand Martin (pilot);

6) RAS Jack Snipe (outside Meijendel).

43 species were trapped more often than the long-term yearly average dictates. For ten of these, 2020 was even the best year since 2000: Great Spotted Woodpecker (10; was 8 in 2015), Sand Martin (9; was one in 2019), the rapidly increasing Cetti’s Warbler (35; was 14 in 2019), Siberian Chiffchaff (12; was 7 in 2017), Savi’s Warbler (7; was 4 in 2013 & 2019), Redwing (171; was 126 in 2001 & 2007), Pied Flycatcher (12; was 11 in 2003), Stonechat (8; was 6 in 2019), White Wagtail (29; was 11 in 2019) and Greenfinch (120; was 42 in 2007). On the other hand, 33 species ‘under performed’.

In all we trapped 80 species, slightly more than the average over the past ten years (78). No new species were ringed. Major misses were Eurasian Sparrowhawk and – for the first time this century – Marsh Tit. There were some surprises in return. The rarest species caught were a Blyth’s Reed Warbler (our 2nd), a Thrush Nightingale (3rd), two Dusky Warblers (5th and 6th) and an Aquatic Warbler (6th). The latter bird perhaps wore the most spectacular foreign ring of the year: it appeared to be ringed along the French west coast the year before. Other interesting recoveries included a Blue Tit ringed in November 2019 and recovered in autumn 2020 in Ventes Ragas, Lithuania. Remarkably we re-trapped a Ventes Ragas ringed bird in Meijendel on the very day we ringed this individual! A Greenfinch reported from France was our first foreign recovery for this species. For Cetti’s Warbler we received our first recoveries to date: we re-trapped both a Dutch west coast and a central Belgian bird, while one of our own birds from 2018 was recovered in the east of the country. A UK-ringed Lesser Whitethroat was a novelty. CES in 2020 was good. The number of adult birds was around the long-term average, while the number of young birds later in the season was relatively high. Feather samples of Lesser Whitethroat and Chiffchaffs were collected for genetic analysis, with a focus on late autumn. A paper on a ten year genetic study on Chiffchaffs was accepted by Dutch Birding magazine, and is due to be published in 2021. With the current Covid-19 crisis, and the West Nile virus being diagnosed in the Netherlands for the first time in 2020 (both on birds and humans), the importance of the nationwide zoonoses studies we participate in was firmly emphasized. In Meijendel, blood samples and cloaca and throat swabs were taken from 214 birds divided over 32 species for this purpose. For a new zoonoses related study we also trapped mosquitos. An international Common Starling study, launched in 2018, was unfortunately postponed for another year due to technical problems with the transmitters. It is now expected to take off in 2021. One of our ringers will lead this study as part of his PhD. Finally, during a special on Meijendel’s nature, our ringing station featured in a well-received programme on national television. The focus was on our long term Common Nightingale data. Fortunately we managed to trap a few during the recordings, so we had something to show as well!

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  • Vincent

It would be odd not to mention the current global crisis.

I know people who have lost relatives, I know underpaid health care workers that run a serious risk of getting infected, and I know people that are on the verge of losing their pub. But when Covid-19 hasn’t hit you personally it’s fair to say that, on the whole, the Dutch have been lucky. We have a functioning government, relatively few people got infected and economically we can take bigger blows than most other countries.

And then there was our so-called smart lockdown. We did not get locked up in our houses. Protected areas and parks are still open to the public, as long as you stick to the rules of social distancing. Which means we can still go out birding: a major difference compared to birders in several other countries I spoke to. And out I went nearly every day.

I had a record number of encounters with Ring Ouzels. Short-eared Owls seemed to be everywhere I went. Asio species are my favourite owls!

One even flew over my house!

And well, I even illegally twitched a Black-headed Wagtail (illegal since it could be considered a gathering). Since it was within my birding territory I just couldn't restrain myself - though perhaps I should have.

Some nice raptors included a few White-tailed Eagles (also with one over my house!)

And sightings of another spring delight: both kite species, like this Red.

There were singing Wood Warblers and a Serin, a Purple Heron and a Caspian Tern, and studying non-breeding wagtail forms is always sweet. That kind of stuff.

The latest addition to the long list of scarcer-but-not-rare-birds was this Golden Oriole.

But despite being out a lot, enjoying returning migrants, and seeing all those smart birds it was my slowest spring to date when it comes to truly unexpected encounters.

Was I getting slow? Are the years starting to count?

Perhaps not! This hybrid House x Tree Sparrow was unexpected.

By finding it I at least proved to myself that I was still keen to some degree. And you know what: it's actually more interesting than many rarities!

I have a thing for hybrids, and I've always wanted to see one of these. I devoted a page to record it properly.

Stay safe and healthy everybody. And who know what late spring has in stock!

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  • Vincent

The 2019 technical ringing report for Meijendel, Zuid-Holland, the Netherlands is out now!

Report (in Dutch) can be downloaded here (pdf; 4MB). The English summary can be found both below and in the report.

SUMMARY In many ways, 2019 was a fairly predictable year for our ringing site in Meijendel, Zuid-Holland, the Netherlands. During 62 days (450 hours) between February and November, we ringed 5470 birds and controlled an additional 716 (13%), divided over 70 species. With the average number of species being 78 over the past ten years, it was therefore a poor year for species diversity. One new species was trapped: Sand Martin. Eight species reached record numbers: Blue Tit, Cetti’s Warbler, Spotted Flycatcher, European Stonechat, White Wagtail, Tree Pipit, Brambling and Eurasian Siskin. We participated in the international breeding bird monitoring project CES (Constant Effort Sites) for the 20thconsecutive year. In 2019 we ringed a high number of adult birds, and a reasonable number of juveniles. Nuthatch was a new CES breeding species, whereas the Wryneck (also new within the CES) was a proven migrant: it was found dead 117 km northeast of our ringing site two days later. During July, the peak season for dispersion of juveniles and the start of autumn migration, we were less active than usual and on the days we were active, the results were poor. The number of young Nightingales within our long-running project on dispersing juveniles was therefore disappointing: over the past 20 years, we trapped fewer individuals in 2017 only. In August we ringed on a regular basis, but the number of birds was fairly low for this time of year. During September and the first half of October long-lasting ocean depressions brought a lot of wind and rain, which seriously limited the number of suitable days for field work. From mid-October to mid-November the weather was generally much more favourable, so until the end of the migration season we were able to ring regularly. The number of birds per day was high during these weeks, with a peak of 328 birds on 19 October. Also, the 26 species trapped on 29 October are worth mentioning. Autumn saw an invasion of Blue Tits and a Goldcrest influx. The rise of the Cetti’s Warbler continued, and for the first time since 2001 Siskins were trapped more than occasionally. For a countrywide survey on zoonoses (diseases that can be transported from animals to humans) – a collaboration between the national ringing scheme and Erasmus University (Rotterdam) – we collected blood samples of 107 birds of 23 species. A Song Thrush we sampled appeared to be contaminated with the Usutu virus (the virus that has decimated Blackbird populations in NW Europe). For the first time since 2009 we did not collect any feather material of Chiffchaffs for DNA analysis. We finished the draft of our second paper on the subject in collaboration with professor Peter de Knijff (Leiden University), which is expected to be published in 2020. The only feathers we collected this year were of a presumed (and later confirmed) Siberian Lesser Whitethroat. In 2018 we were involved in a pilot study on Common Starlings, an international collaboration between the national ringing scheme and German (Max Planck Institute) and Swiss researchers. Although the pilot was successful, the start of the project was unfortunately delayed due to both technical and financial complications. As soon as these issues are solved, we are ready start the fieldwork for this study. Hopefully we can pick this up in the near future. Outside Meijendel an additional 414 birds divided over 16 taxa were ringed (including ten species not ringed at our regular site) for several RAS (Retrapping Adults for Survival) projects (Jack Snipe, Barn Swallow, Yellow Wagtail), or for educational purposes. Thereby a grand total of 5884 birds of 80 taxa were marked by our ringing group in 2019. Other highlights included our chairman Wijnand Bleumink being appointed Ringer of the Year 2019 by our national ringing scheme and the Ringersvereniging (the association that represents the interests of ringers). A well-deserved acknowledgement for a devoted volunteer who has been a fully licensed ringer since 1958. An article on Nightingales by Peter Spierenburg and Morrison Pot was published in Holland’s Duinen. It describes the correlation between the density of territories from year to year (based on breeding bird surveys and our CES data) and fledged juveniles (based on our ringing data of dispersing juveniles). In short they are negatively correlated: the higher the density of breeding pairs, the lower the number of juveniles. Peter gave a lecture in front of a large audience during the Sovondag, the biggest birdwatcher’s fair in the Netherlands: a fantastic way to promote our work.

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