Tree management at Osterley Park

Here is an example of a situation where removing a tree is beneficial.  In the picture below you can see two Oaks growing side by side.  One is a deciduous English oak (Quercus robur), the other smaller tree is an evergreen holm oak (Quercus ilex). The English oak is somewhere around 350yrs old and is of great ecological significance to the estate here. The holm oak is about 30yrs old and offers little habitat value.  The evergreen and fast growing nature of the holm oak means it is threatening to overshadow the lower crown which can be seen developing on the English oak.  This old English oak will be relying on developing a healthy lower crown to continue living for the next few hundred years as it starts to ‘grow down’ and become a shorter squat tree.  The evergreen holm oak will soon double in height and spread, dominating this area.

  Holm Oak near veteran English oak

Here is a second picture taken after we removed the holm oak. Not only has the English oak now got room to spread out its branches, but the maples behind will also benefit. The next point is subjective, but I also prefer the open feeling created from retaining deciduous trees when there is little light in winter and early spring months, and the view of the colourful maples behind. What do you think? 

Holm oak gone near English oak


The oldest tree.

old tree

If only trees could talk

This beautiful English oak (Quercus robur) is 650 years old and the oldest tree in Osterley Park. 

Just think of the many global events that have happened during its growth since growing from a sapling in 1364!

With circumferences of Oaks ranging from 4m to 12m, at 6.5 meters, it took a group of 5 people with arms fully stretched to encompass this tree! 

Carla Malcolm (Assistant Warden) – the smiling female in middle of picture.

Barn owl(s) about

barn owl kish 2

At Osterley we are lucky enough to have a group of enthusiastic birders who report in their sightings. One of the highlights this year has been a barn owl hunting in an area of  rough grassland adjacent to Osterley Park.  One of the group, Kish Woolmore, has been kind enough to let me post some of his fantastic photographs of a barn owl hunting. In one of the photos you can see what is most likely a field vole being grasped by the talons of the owl.  Barn owls used to be the most common species of owl in the U.K, now only about 1.4% of farms are home to barn owls. 

Barn owl kish

Even more batty!

The London bat group brought a group of people to listen to bats at Osterley this year. The group was learning how to use bat detectors. after spending the night listening to the calls and deciphering wich species are present, they deduced that we have Leisler’s bat(sometimes called lesser noctule) in the park. Nationally, this bat is much less common than species such as common pipistrelle, although more abundant around West London. 

A hunt for Nathusius’ pipistrelle in the estate has also confirmed their presence here.  Along with recordings of common pip, soprano pip, daubenton’s, noctule and a record of brown long-eared bat from 1983 we have 7 species at Osterley – not bad for a property 5min from Heathrow!

Nyctalus_leisleriLeisler’s or lesser noctule bat


A walk along the lake edge

Some more observations from Mark Russell.

800px-Bumblebee_October_2007-3aBuff tailed bumble bee. Bombus terrestris.

Dear Jeremy,

I took a walk along the bank of the MiddleLake today. Absolutely wonderful to see what was going on. The stools/snags/rootstocks are regenerating coppice-like. The ash looks, thankfully, disease-free. The elm, now fourth or fifth generation, likewise. And could that be a sweet chestnut I saw as well? I can’t remember seeing a mature one growing at that location. Please advise!

The flowers of water mint encroaching the bank were being visited by red and buff tailed bumbles, cuckoo bees, hoverflies and day-flying beetles of several sorts. Common blue, gatekeeper and wall brown butterflies were there too.

A few blue-tailed and red eyed damsels were still flying. This is the latest calendar date that I have ever observed Zygoptera. No Anisoptera to report today. Very odd!

Today’s highlight for me, however, was the observation of a colony of cinnabar moth larvae devouring the ragwort that has been allowed to grow.



Damsels at Osterley (updated)

Mark Russell is a keen naturalist, supporter of Osterley Park and member of our volunteer birding group. He often sends me his observations which I thought I would share on this blog – thanks Mark!

Hello, Jeremy,
Today was the first time for a month that I’d been able to take a walk round Osterley Park.
I attempted a deliberate, non-bird walk round the lakes. It was good to see Common Blue, Blue Tailed and Red Eyed Damsels still going strong along with two, male, Black Tailed Skimmers on patrol. The water level in the Middle Lake was commendably high which has surely helped emergence along with the sturdy, marginal vegetation which was looking great and attracting and hosting some invertebrates way beyond my powers of identification. I also observed meadow brown, comma, small skipper and green-veined white butterflies along with other day-flying and/or disturbed micromoths.
The best bit though, was when a visitor to OP approached and asked me if I could tell her about the seagull she’d seen flying into the water head-first.
She had seen a tern fishing and as I began to explain, a gathering of other young people who had also seen it became genuinely interested too.
Some non-bird walk! This enthusiasm made my day.

610px-Black-tailed_SkimmerBlack Tailed Skimmer


Hello Jeremy.
Good to see you today.
All three species of previously reported damsels were still flying, some in tandem. It really is a remarkably late season.
One dragon, a Brown Hawker was on patrol over the water near the island on the Middle Lake. Brilliant. This is only the second time in three years that I’ve seen this one at OP so it’s nice to hope that it may be home-grown.
Small Copper butterflies were feeding on the flowers of water mint along with good numbers of the other browns mentioned previously.
The Cinnabars have eaten all the ragwort foliage and only three larvae remain in a hopeless search for food. I hope some of them managed to pupate before they started eating each other, unless of course, these are three, lucky cannibals.
Examining the defoliated host plants, I noticed a solitary, bright yellow looper, about 10mm in length and =>1mm in diameter, around the calyx of one of the flowers. I’m trying to ID it. Any ideas?
brown hawker Brown Hawker

Tufted traveller

tufted duck saddle

National Trust animal ecologist Peter Brash recently picked up on a tufted duck with a nasal saddle on the garden lake at Osterley Park. These saddles are an alternative to ringing and do not harm or bother the ducks. Here is what Peter had to say about this duck. (photo courtesy of nmahieu from flickr taken on the Thames at Fulham).

Hello Jeremy,

I’ve just received the info on the male tufted duck I saw at Osterley on 8th and 9th June.

It was given a nasal saddle (a piece of plastic with number and letter codes) at Braud-et-Saint-Louis, France on 16th April. According to the person who rung it, it was being held illegally captive by hunters. Braud-et-Saint-Louis is a little way north of Bordeaux so the bird flew at least 450 miles to arrive at Osterley.

The bird was rescued from the hunters and given its nasal saddle before being released. I can only presume that the hunters were using it as a live decoy to lure other birds in. Awaiting more detail from the ringer.

Turns out tufted ducks can get as far away as Siberia and Pakistan after being rung in Britain, so 450 miles isn’t very far!