Facts about Osprey Identification

Dyfi Osprey leg rings 3R and 5R


Fact 91

In the UK ospreys from Scotland are (Darvic) ringed on the left leg while ospreys from Wales and England are ringed on the right leg. Around 40% of osprey chicks are ringed in Scotland; in Wales and England 100% of all known nests are ringed each year.

Fact 92

When ospreys are ringed they are usually fitted with two rings. The first is a metal British Trust for Ornithology (BTO) ring which has a unique number and an address so that finders can send details to the BTO as part of the national bird ringing scheme. The second is the plastic Darvic ring which can be viewed from a distance with binoculars (if you're very close) or a telescope (up to around 250m maximum for ospreys with a quality scope and good eyes!).

 Glesni with her BTO ring on the left leg and Darvic ring on the right leg - Blue 12
Fact 93

Osprey chicks are ringed at around 35 days old. At this point in their lives they are almost fully grown which means the ring will fit well, but they have not yet fledged which means they can be handled in the nest and won't fly away.

Dyfi osprey ringing in 2014 - Deri and Gwynant.

Fact 94

The Darvic ring gets its name from the type of plastic - Darvic PVC sheeting - that they are made out of.

Fact 95

Darvic rings are usually referred to by their two colours, eg Blue/White, where Blue is the colour of the ring and White the colour of the lettering.

Fact 96

Most Darvic rings have two characters (figures or letters) on them, however since 2012 birds ringed in Scotland will generally have three. The very early rings only had one character.

Fact 97

Rings should be fitted so that they read from the foot up although you will sometimes find one fitted the wrong way round.

Fact 98

Across Europe different countries have now adopted different colours for ringing ospreys. The UK uses Blue rings, Germany uses Black, France uses Orange and Spain uses Yellow.

Fact 99

There are a number of different features that are used to identify ospreys who don't have leg rings. These include distinctive feather patterns and individual differences that can be seen in the eyes.

Dai Dot has a cluster of iris dots in the 4 o' clock position, left eye.
Fact 100

Osprey identification is not an exact science and is extremely difficult unless a bird lands or perches near the nest so that photographs can be taken. Whenever we see an osprey at the Dyfi nest we try to photograph the bird in as much detail as possible. This helps us to build a record of different birds and helps us to identify them from year to year. 

We like to name unringed birds (Dai Dot for example) as it is a lot easier to refer to them as they have no leg rings.