Spring sunshine at Dundreggan

The week after the planting of our Millionth Tree (on 20th May) we finally had some warm sunny weather, and as it happened I had a couple of days scheduled to be at Dundreggan in that time. On one of the days the Scottish staff of the Woodland Trust were making a site visit to Dundreggan for their annual field trip, so I joined Steve, our Operations Manager at Dundreggan, and Jill and Allan, the other two full time staff there, in hosting the group of 24 people.

As with many other visiting groups, we began with feeding the wild boar (Sus scrofa) and explaining their role in reducing the prevalence of bracken (Pteridium aquilinum) in the birch woodland there. Steve showed them some of the tree planting we’ve done, and Jill talked about the work of our tree nursery there. We also had a good discussion about deer management, and the group asked a lot of perceptive questions, as they are involved in a similar project at their own Glen Finglas property in the Loch Lomond and The Trossachs National Park further south in Scotland.

Their visit ended in the early afternoon, and Steve and I had some time afterwards to discuss work and plans at Dundreggan. The last of our Conservation Holiday groups for the spring was taking place in our tree nursery there that week, and the volunteers had seen a chaffinch nesting in the lichen-covered branches of a tree just outside the lodge. They showed me the superbly-camouflaged nest, which had three chicks in it, so I spent the latter part of the afternoon watching and photographing them, before heading for home.

This was particularly exciting for me, not only to see the very well-constructed nest and the chicks so close up, but also because I was about to write the next in our series of Species Profiles, for mailing to our members, and it was scheduled to be on the chaffinch! Although I had some photographs of male and female chaffinches to go into the profile, I didn’t have any of their nesting behaviour or of chicks, so this was a perfect opportunity to fill those gaps in my photographic coverage, just in time to use the images in the Species Profile.

I spent over an hour watching them altogether, with the chicks being still and motionless in the nest until the female approached, at which point they became very active, with their mouths gaping wide for food. I saw the female bird make several visits with insects for them, and on one occasion a male chaffinch came close to the nest, but didn’t feed the chicks at all. I subsequently discovered, in researching the profile, that the male plays no part in feeding the chicks until they leave the nest. At that stage they’re still dependent on their parents for food for another two weeks or so, and that’s when the male joins the female in feeding them.

It was time to go home then, but I returned to Dundreggan a couple of days later, on the week-end, hoping to get some photos of the chicks. I had seen on the first day that they were already quite large, and as they fledge about 14 days after hatching I knew they wouldn’t be in the nest for much longer. In fact when I arrived there was just one chick still at the nest – the other two must have fledged in the intervening day.

The female was still coming to feed this last one, although it was clambering around outside the nest, seeking shade from the sun, and it looked like it would soon fledge too. I only got a few photos of it that morning, as the lighting conditions were quite difficult, due to the brightness of the sun and the contrasting deep shade. However, I did manage to shoot a few video clips as well:

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Leaving the nest site, I had a look at a mature sycamore tree (Acer pseudoplatanus) on the other side of the lodge. Although sycamore is not native to the Caledonian Forest, this one had been planted as an ornamental tree around the building and we have no plans to remove it. In fact it harbours some interesting wildlife, including some spectacular galls induced on its leaves by a mite, that I had seen there last year.

This day I was looking for aphids, and I quickly found there were lots of them on the undersides of the leaves and on the leaf stems themselves. I took quite a lot of photographs and also collected some specimens, which I sent to Ed Baker, an aphid specialist who’s coming up to Dundreggan to do a survey for us in June. Although he hasn’t had an opportunity to study the specimens in detail yet, he said that in the photos he thinks there’s 3 different aphid species that commonly occur together on sycamore.

There certainly looked to me like there was more than one type of aphid on the leaves. However, because each aphid species in general has more than one form (eg nymph or adult etc), depending on the stage of development it is at, it is hard to distinguish what may be different forms, instead of separate species. That’s where expert advice is essential, and I’m hoping to learn a lot more about aphids while Ed is doing his survey.

Leaving the sycamore tree behind, I walked towards the birch woodland, and just at the edge of it, my eye was drawn by some bluebells (Hyacinthoides non- scripta) that were being visited by a bumblebee.

 

 

 

 

 

 

Walking through the woodland, I came to the Aspen Burn and decided to have lunch there, as I could look for more aphids on the aspen trees (Populus tremula) as well. As soon as I sat down to eat, I saw a bright red beetle land on the stem of a young bracken frond in front of me. Looking a little like an elongated version of a ladybird, this is a species (Clytra quadripunctata) that lives as a larva inside the nest of wood ants. There are several wood nests very near to where I was sitting, so it may be that this individual was a newly-emerged adult from one of the nests. While I ate my lunch and watched it, another two beetles of the same species landed close by. I wondered if they had all just emerged as adults?

I’d seen aphids (Pterocomma tremulae) feeding on the aspens there in previous years, and in looking at the same branches, they were there again now. They suck the sap of the aspen from twigs, and are tended by wood ants (Formica lugubris). The ants harvest the honeydew that the ants excrete – this is a clear liquid that forms one of the major food sources for the wood ants.

The ants stroke the aphids with their antennae, to stimulate the excretion of honeydew, and will also ‘farm’ the aphids, even moving them around from place to place on the aspen twigs, to encourage the production of more honeydew. The aphids themselves go through several moults as they grow, and eventually some winged adults are produced – the ones in these photographs are nymphs, as the younger non-adult forms of aphids are known as.

The mature aspens seem to cope with the loss of sap to the aphids without any ill effects, but some aspen suckers nearby that we protected with Netlon tree guards mysteriously died after one year. I’d seem them covered with aphids in late summer, so I wonder if somehow they weakened the suckers so much that they didn’t grow any more the following year?

On one twig I saw an aphid that looked slightly different, particularly in its shape, and when I sent the photo to Ed Baker, he thought it might be a ‘stem mother’, or fundatrix, for the same species (Pterocomma tremulae). These are females that give birth to live young aphids, and do so parthengenetically – ie without the need to mate first. This is one of the ways by which aphids are able to reproduce very quickly, sometimes reaching huge numbers on a host plant.

After spending a while photographing the aphids, I walked on up through the birchwood, towards the top edge, where there were some good views on to the forest, set against the blue, virtually cloudless sky.

 

 

 

 

Scattered in amongst the upper sections of the birch woodland I found a lot of primroses (Primula vulgaris) in bloom. This was a dramatic indication of the extended spring we’ve had this year, as it was the 26th of May – 3 months since I’d seen the first primrose in flower at Dundreggan, on 25th February!