April has passed and a considerable number of photographs
have been taken, creating the biggest block of photographic data for this part
of the year (Figure 1) that the HRS has assembled. Two points can be recognised. Firstly, the contribution
of the UK Hoverflies Facebook group has been very significant. Secondly, that
numbers of records derived from Flickr and iSpt etc have held up, despite the
shift towards Facebook where several of the most active photographers now post
their shots
 |
| Figure 1. Five-week running means of photographic records for the years 2011 to 2014, with the 2014 records represented as all records and a sub-set from sources other than Facebook (the situation that obtained before 2014). |
The two trends offer a very positive indication of growth in
hoverfly recording, which is very encouraging. It helps to show that the
strategy that Stuart and I embarked upon five years ago is paying dividends. At
the time, we were concerned that recruitment of new recorders was pretty low
and that we were not connecting with people. That point represented a watershed
between the traditional recording scheme and society-based approach to
engagement, and more pro-active approach using 'virtual societies' where we set
out to make contact by engaging locally. Our training programme has certainly
had this effect and the internet has greatly expanded the basis for recording.
Translating this into the full-spectrum recording that the old guard of the HRS
have done may take a while longer, but even if only 5% of enthusiasts buy a
microscope and start to look at preserved specimens we should replace the old
guard with a new generation!
I think that the community of photographic recorders may
also be extremely helpful in developing knowledge about yearly changes in
phenology amongst more abundant and obvious species. This could be extremely
interesting if developed as long time-series data. By way of example, two graphs
are indicative - the first being a selection of spring species (Figure 2) and the second
specifically Epistrophe eligans in
2014 (Figure 3).
 |
| Figure 2. Five week running means of combined photographic data 2011-2014 for a selection of spring hoverflies. |
 |
| Figure 3. Numbers of photographic records of Epistrophe eligans in spring 2014 - data to 4 May and consequently incomplete. |
The data for spring species are combined for 2011-2014 and have been smoothed by a five week running mean. I will look in more detail at individual year data but everything is a bit skewed by larger numbers of records from 2014 and much more limited numbers in some years. I have simply posted the data for 2014 for Epistrophe eligans because in past years this species has not figured greatly in photos. The graph will be updated at some point because this species' flight season is not over. The trend is obvious though!
