Fish Stats

Every single fish that the Dyfi ospreys catch, we record it.

Monty may have a sneaky one now and again when there are chicks present and he needs a little time away from the family, so we can't record these obviously, but we don't think there are many.

Ospreys throughout the world eat hundreds of different species at different location/nests, but there will usually be one fish species that is preferred over any other. At the Dyfi, that species is the grey mullet.

Don't tell him Pike




The grey mullet makes up approximately 43% of the osprey's diet with flounder making up around a fifth of the diet at 20% and trout a third at 33%. These ratios can change throughout the season, but once averaged out over each summer, and between seasons, there is remarkable consistency.


Please note: we split the two trout morphs into 'sea trout' and 'brown trout', as phenotypically (what they look like on the outside) they are different. However, they are, in fact, genetically the same species. 


Over the years we have theorised that Monty may catch specific fish species dependent on environmental factors at the time such as tide phase, temperature, wind direction and so on. However, three scientific studies have shown to date that there is no scientifically significant correlation between species caught and any of the environmental parameters we have measured. He seems to catch when he (or the family) is hungry, and whichever species he finds the first.


DOP staff collect this data and volunteer Vicky kindly produces these great fish pies and charts for us. They take a lot of effort and time every year - a huge thanks to all.

Cumulative Fish Stats for all breeding years, 2011 - 2017 inclusive


Weekly analysis of fish data for previous year - 2017

With many thanks to volunteer Vicky King who makes these wonderful graphics for us from some boring looking data every week/year.