Saturday 29 October 2011

Conserving Habitat for Forest Birds


Nature Notes for October 28, 2011

Time after time when I write articles about a single species of bird, I have to report that the population of this species is declining due to habitat loss. Last Saturday, I attended a workshop which aimed to address this issue with regards to forest birds.

Called “Conserving Habitat for Forest Birds: A Workshop for Forest Owners and Land Managers”, the day included a guided field trip to Peter’s Woods and indoor lectures.

On the walk through Peter’s Woods, we were encouraged to really observe the structure of the forest. What species of seedling trees were regenerating? (Mainly sugar maple)

Our attention was drawn to fallen trees which create openings in the forest canopy. This allows more light to reach the forest floor and enables seeds that need more light to germinate. As well, the fallen trees often created pit and mound structures where the root of the tree had been pulled out of the soil. These structures create microclimates which encourage the germination of different species of tree seedlings.

Our attention was particularly drawn to dead trees with woodpecker holes in them. These holes are necessary for the survival of other birds and animals which cannot create their own holes.

We were reminded that forest habitat is constantly changing. In a dramatic example, a large dead tree had fallen near the trail since the leaders had surveyed the woods five days earlier in preparation for the workshop.

The lectures attempted to relay to the participants the latest research in forest management techniques. These techniques can prove profitable to the land owner and provide a more diverse habitat for those living things – both animals and plants - which need forest to thrive. All living things are interconnected, so biodiversity is very important. We can never tell the result of removing one species from a community.

Prior to European settlement, most of southern Ontario was covered by forest. In the mid-nineteenth century, most of this forest was cleared both for the timber and to make fields for agriculture. By the mid-twentieth century, some area were being reforested. There was some recognition that forests were necessary on the Oak Ridges Moraine to prevent chronic flooding downstream.

These new forests, however, did not have the same structure as the original forest. Many were plantations of trees all the same age, planted in straight rows. In Northumberland County, the two major forest tracts are the Ganaraska and Northumberland Forests. These are now more than 60 years old. Timber has been harvested from these forests, but the intention is to keep them as forest.

Managing a forest requires long term planning. We were presented with figures that indicated that in the long term, a well-managed forest could provide more income than the neighbouring agricultural land. The difficulty for a landowner who needs to make a living from his forest is that the income is not paid out annually.

Current forestry practices tend towards diameter limit harvesting. That is, all trees above a certain size are cut. The workshop presented several other options for cutting – group selection, stand improvement and/or single-tree selection. Landowners might want to consider a combination of these harvesting options depending on the make-up of their own woodlot. The important thing is to have a plan.

Some common forest bird species are showing population declines. By developing a plan to manage a forest, these species have a better chance of remaining common.

All of the participants took home a new Ministry of NaturalResources publication titled A Land Manager’s Guide to Conserving Habitat for Forest Birds in Southern Ontario. This book allows participants to review the information presented in the talk. It also includes a list of other sources of information, both print and electronic resources, for those wanting to delve deeper into this issue.

Saturday 15 October 2011

Common Eiders a rare Visitor


Nature Notes for October 14, 2011

In the three days which passed between the writing of the last Nature Notes column and its appearance in print, the birds in the area changed from lingering early season migrants to good numbers of the later-expected fall migrants.

Then the weather changed again. The mild temperatures last week and over the Thanksgiving weekend caused the migration to slow yet again. As long as the weather stays warm and food is available, there is no urgency for the birds to leave.

The fair weather conditions have been accompanied by light winds and a full moon. Perhaps many migrants are just flying over, undetected by observers on the ground.

Despite the name, two female Common Eiders spotted in late September in the offshore islands at Presqu’ile Provincial Park have been the rarest birds seen to date this fall. The single Common Eider, seen on October 1 and 2 off Chub Point south of Grafton, may have been one of the Presqu’ile birds.

This large sea duck is common in the high Arctic, the Maritimes and the Gulf of St. Lawrence, but it is quite rare on Lake Ontario.

Prince Edward Point Bird Observatory is reporting a good movement of Northern Saw-whet Owls. The peak of their southward migration through this area is usually in mid-October. Because they are highly nocturnal, most pass through without humans ever being aware of them. Some winter in Ontario but some go as far south as the mid-Atlantic states of the U.S.

Both Golden-crowned Kinglets and Ruby-crowned Kinglets have been abundant this week. These tiny birds are usually detected by sound. The Golden-crowns have been giving their high pitched call notes from neighbourhood conifers. The Ruby-crowns call note is lower pitched and wren-like. There seems also to be an abundance of tiny flying insects which provide food for them and other small land birds. In amongst these flocks, there have been a few WinterWrens and Brown Creepers, both later fall migrants.

Hermit Thrushes could be heard chucking from the underbrush. These are the last of Catharus thrushes to leave our area. Some do nest in the conifers of the Ganaraska and Northumberland Forests. Many of theses migrants have come from much further away in the boreal forest. They winter from the continental U.S. as far south as Central America.

Warblers can still be found. Most are Yellow-rumped Warblersand Palm Warblers, but a few others could be found during the past week: Nashville, Common Yellowthroat, Magnolia and Orange-crowned.

Although I haven’t seen them in large numbers, White-throated Sparrows are trickling through. A few White-crowned Sparrows can sometimes be found with them. The White-throated Sparrows breed as far north as the boreal forest. The White-crowns breed even further north on the taiga. There is a lot of overlap in the wintering range of these two species. White-throats stay mostly in the continental U.S., while White-crowns winter range extends through Mexico into Central America.

Dark-eyed Juncos have become more abundant in the past two weeks. This sparrow, too, breeds in the boreal forest. It is a regular at bird feeders and many winter in our area.

Although none have yet visited my backyard feeder, flocks of Pine Siskin could be heard passing over during the past week. This small finch breeds in the boreal forest. In some years, it irrupts south in response to food shortages in the northern forest. The local tree seed crops will determine whether the siskin will stop here.