Search for the Silver Colonel

Silver Colonel soldierfly
Photo by Simon Knott

The Silver Colonel soldierfly (Odontomyia argentata) is a rare species with less than a hundred records on the recording scheme database. It has been recorded from 21 vice-counties altogether, but only 11 of those counties have records from the 21st century. On the other hand, there have been new county records for Hertfordshire, Leicestershire and Warwickshire since 2013, with the latter two counties representing a considerable extension north in its distribution. As usual it is difficult to be certain how much of the loss from some counties and gains in others is due to genuine change in the species' range, and how much due to variations in recording, but there does seem to be a genuine mix of losses from some southern sites and gains in the midlands. We'd like to have a better idea of how this species is doing, and the only way to find out is to do more recording!

If you find this species please do add the records to iRecord, preferably with a photo if you can, or send them in to the scheme via one of the other routes. If you visit one of the known sites and don't find the fly please let us know that as well. Help with identification is always available via the soldierflies Facebook group, or on iSpot.

When to look

Odontomyia argentata flies early in the year, starting in mid-April but with the majority of records in May, fading out in the first week of June.

Phenology chart

 

How to recognise it

It is a species found in fens and marshes, where its larvae have been found in shallow pools and ditches. The adults are slow-moving flies, like most soldierflies, and can be found sitting on the vegetation or visiting flowers, including hawthorn and willow catkins. Odontomyia argentata is reasonably easy to recognise, especially in the male which has the distinctive silvery hairs on its abdomen that give the species its name. The hairs can appear dull from some angles, so try to get a view of it in good light, and if photographing take shots from several angles. Many thanks to Graham Calow for the images below (to which I've added annotations). More of Graham's photos can be seen at NatureSpot, and see also Steven Falk's Flick collection for this species.

identification features

 

Where to look

It is worth looking out for Odontomyia argentata in any fen, marsh or reedbed site in southern England, and also in wet woodlands if they have clearings and pools. Look around the edges of shallow pools and ditches, and on nearby flowers. Andrew Jukes reports finding one in a very small fen next to a car park in Bristol, so don't rule out tiny sites!

The map below shows all the 10km squares for which the recording scheme has records (red = recorded since 2000, blue = recorded between 1950 and 1999, black = recorded before 1950). There are bound to be records missing from the scheme database, either because they haven't been sent it, or are in the backlog waiting to be dealt with - if you know of records that aren't shown on this map please get in touch. There are a few additional records (including one in south Wales) on the NBN Gateway.

Here are the records summarised by vice-county, with the most recently recorded counties first.

Vice-counties with records of Odontomyia argentata
Vice-county Earliest Latest Records
Leicestershire 2014 2015 4
Hertfordshire 2014 2014 1
Warwickshire 2013 2013 1
South Hampshire 1897 2008 15
Surrey 1948 2005 5
North Essex 1921 2004 5
Berkshire 1985 2003 4
North Hampshire 1970 2003 11
East Norfolk 1924 2001 12
West Norfolk 1948 2000 5
West Suffolk 1909 2000 7
North Wiltshire 1996 1996 1
Cambridgeshire 1924 1990 6
East Suffolk 1943 1989 3
Huntingdonshire 1949 1966 2
North Somerset 1927 1949 2
West Kent 1948 1948 1
Dorset 1947 1947 1
Bedfordshire 1944 1944 1
Middlesex 1805 1926 2