Wednesday, 23 November 2016

Verifying iRecord

I have finally completed the iRecord verification process for data arriving between April and November 2016. There are about 220 records remaining to be verified once there have been changes to the species dictionary.

Last year I tried to make sense of the data but failed to separate out the records supported by photographs from those that were not. This year I learned from my mistake and ran separate logs so it is now possible to see what is going on! Table 1 presents the basic data on the time spent, numbers of records verified and the types of problems encountered. The significant figure is that around 10% of the photographic records have required some level of adjustment, with about 6% outright misidentification. The biggest howlers were a sawfly logged as Platycheirus granditarsis and what appeared to be a water trap full of thrips attached to another record that seemed to be OK. There was also a ladybird posted as Volucella zonaria!

Table 1. iRecord basic data

As a first stage in analysis, I have split the tabulation of mistakes into a series of units, mostly around Tribe, but in places simply a lumping for convenience!The ID given by the recorder is in the left hand column and the correct ID is in the top row.

Table 2. iRecord corrections for Bacchini for data updated in 2016

Table 3. iRecord corrections for Cheilosini

Table 4. iRecord corrections for Eristalini

Table 5. iRecord corrections for for Merodontini, Chrysogastrini, Paragini and Pipizini

Table 6.  iRecord corrections for Syrphini

Table 7. iRecord corrections for Volucellini corrections

Table 8.  iRecord corrections for Xylotini

These data show two discrete sets of problems:

  • basic mis-identifications, which make up about half of the problems; and
  • over-confidence in attributing names where it really is not possible to take photographs to species.

Relatively little can be made of the data that are not supported by photographs as all one can do is to use a bit of inspired judgement! A few interesting problems were encountered, such as records from Northern Ireland by relative novices that were unlikely. A record of Rhingia rostrata in particular exercised me as it was some distance further north than its northern limits in England. This coupled with my belief that R. rostrata does not occur in Ireland led to that species' exclusion. Another was a record of Eristalis cryptarum that later turned out to be Sericomyia silentis. Apparently the contrived name 'bog hoverfly' applies to both species, so we must watch for more of these glitches.

I will perhaps do a little bit more analysis in due course, but the figures tell their own story!

No comments:

Post a Comment