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Forest Diary

The Forest Diary, ManagementFemale Tawny owl
of Milton Abbas woodlands
yields tawny owl success

By Mark Warn, Wildlife Ranger


(enquiries.southern@forestry.gsi.gov.uk)

Did you know the woodlands situated alongside the pretty village of Milton Abbas are home to some very special residents? Nestled inside 40 bird boxes are 38 young, tawny owl chicks and yes, they are very cute and very fluffy!

Back in 2012, I set up an exciting new project with Danny Alder, Dorset County Council’s Ecologist to attract tawny owls to nest in these woodlands to help improve forest management and increase the understanding of this much loved bird.

The silviculture (the process of tending, harvesting and regenerating a forest) of the two mixed, broadleaf woodlands at Milton Abbas School and the Whatcombe Estate, appeared to be the ideal environment for tawny owls and we knew from sightings, a population was already in residence.

Working in his spare time as a British Trust for Ornithology (BTO) ringer of birds, Danny constructed the bird boxes from durable western red cedar wood sourced from a local sawmill. Dorset County Council recognised the value of our work by kindly funding the timber for the boxes.

We then worked together to put up the 40 boxes at 500 metre intervals to get good coverage across the woodlands. Tawny owls are notorious for aggressively defending their nesting territories from others tawnies so the boxes have to be spaced out to avoid all out warfare of the feathered variety.

The density of the woodland at Milton Abbas is good for the Tawny owl population as they can find most of their food and shelter in a relatively small area. The understorey offers cover for small mammals. The owls favour rodents as prey, enjoying a meal of wood mice, yellow necked mice, field and bank voles, common and pigmy shrews. Rarely they are predators of bats and will even prey on their own young if food is scare. We identify their prey from the items we find in the nesting boxes so they have no chance of hiding what they’ve been snacking on the night before! 

So what happens once we’ve put the bird boxes up?

Tawnies are an earlier breeding species so we need to ring the young before they fledge. Females start to lay their eggs early in March and the young hatch out late March to April. Every April with the help of a trusty ladder, we climb up each tree housing a numbered box to check for new chicks.

 I have to say there is nothing better than that feeling of peering into the boxes to find several pairs of eyes, surrounded by a ball of fluffy feathers, looking up at you!

We then use a BTO ring to ring any chicks once they’re big enough. Danny together with experienced bird ringer Dr Simon Lane has a BTO license to ring the birds. We do this with trainees under close supervision. By ringing them, if they’re recovered anywhere else, we can check how far they have ranged and know how old they are. We also weigh them and take a measurement of their wing length. All the information is sent to the BTO and they feed it into their long running national data set for monitoring purposes. The tawny owl is one of their priority monitoring species in woodlands so they’re keen to check changes in their annual productivity.

Tawny owls are located at the top of the food chain as a key woodland predator. They are distributed across the country and are an indicator of good woodland management. Monitoring their populations to check they’re not declining is crucial as this could reflect something amiss going on in the environment locally or even nationally. It also helps us to build an understanding of the dynamics of the species in the Forest and furthers our knowledge of the ecological food web, which the species is an intrinsic part of and depends upon.

The project, now into its third year, is a great example of partnership work and the good uptake of the boxes is a success story in its own right. So far this year, we’ve had a 33% box occupancy rate totalling 38 chicks. We even found one brood of 5 young, significantly more than the usual 2 to 3.

Both Danny and I hope to secure future funding to continue this valuable work. It’s clear in my role as Wildlife Ranger that when I talk to people who visit the woods at Milton Abbas they recognise the true value of this project. Let’s face it who doesn’t love the wise old owl!

For more information on the work of the Forestry Commission visit www.forestry.gov.uk