State of the Syrphs - 1-Dec-2023

Hi everyone,


I want to start by thanking all those of you who were involved in the 'Annotatathon'. Over that weekend we added a splendid total of 33 044 annotations! I would be surprised if we didn't now have the best annotated national Syrphid fauna of any (large) country on the planet :-). Incidentally, if you want to contribute annotations abroad you can use much the same rules - in relation to sex annotation Syrphini in particular are safe, most of the new exceptions will still be in recognisable groups like Helophilina. Just beware that the Microdontinae are far more diverse abroad, and there are more exceptions to the eyes rule in the Merodontini (especially Eumerus) but you can still tell that the male eyes are converging rather than diverging as in females.

Anyway, this is what our efforts look like zoomed out to the whole duration of the project. (I haven't recorded this information regularly unfortunately, but you get the picture!)

I know some of you have continued to add annotations since the event, which is great - please do continue to use the links in the main post for that. (I need to work out a strategy for dealing with the slightly strange issue that arose with dislodging old observations with a high proportion of obscured locations to HRS. One way that you could help is by changing the geoprivacy on any of your old observations with obscured locations to pinned locations.)


In the more regular way of looking at monthly annotations we have also done well. There were fewer than 400 new observations in November which makes things easier, but even so yes, that 'life stage' data point is at 100%!


There is plenty to be pleased about on the NeedsID front as well. The total size of the Needs ID pile is nearly back to where it was at the end of July. Only 6 genera have increased (and not by much), with 40 unchanged and 24 down. The biggest % fallers with >50 obs to start with were Sphaerophoria (-50%), Episyrphus (-29%), Eumerus (-17%), Dasysyrphus (-15%), Epistrophe (-8.4%) and Eupeodes (also -8.4%). It's particularly nice to see such a big % fall in Eupeodes, the neediest genus. Personally, I will finish my assault on Sphaerophoria soon and move on to Eristalis. Feel free to let us know what you're up to in the comments!

Don't feel like you have to be restricted to the really big genera though. HRS like it when unusual species records roll in! Why not have a pop at learning Sericomyia, Xylota, Chrysotoxum or Xanthogramma? A couple of words of advice:
1) See the resources page
2) Don't forget to check that the genus is correct before you ID the species!
3) Try not to be overconfident - it is better not to ID than to over-ID.
4) Having said that, don't be afraid of making a few mistakes, it's the best way to learn.
5) You can always tag one of the recent top identifiers into the observation to ask questions. This is especially useful if you think it's a rare species - you're probably wrong by definition so it's always best to check!
6) Don't feel pressure to do loads. Take the time you need to be confident.

Obscured Locations

I thought it would be interesting to see what is happening with obscured locations. Observations with geoprivacy set to 'obscured' cannot be used by UK recording schemes (but they are still sent to them, they just have to reject them because they cannot see a sufficiently accurate location, wasting time and energy). So NBN are encouraging people to use pinned locations instead (it is ultimately each user's choice though, how to manage their privacy). The graph below will not be particularly accurate, because it fails to reflect that some people changed their old observations when the project started, but before I gathered this data (that includes myself!). In other words, the numbers in the past would have been higher than this graph suggests. This seems encouraging, even if November's very low figure is probably an aberration due to the low overall numbers. Thanks everyone!

Further events

I'll have a think about what other events might be worth doing over the festive season! Ideas welcome.

Thanks again,

Happy Advent: "God bless us, every one!"

All data compiled on 30-Nov-2023

Posted on December 01, 2023 12:00 AM by matthewvosper matthewvosper


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