Maintenance and cleaning of the 41 monitored nestboxes along the Bluebird Trail began on 7 March, 2002. All of the boxes were in good to excellent condition and replacement was not necessary. One slot box was changed to a U box on 24 April after starlings repeatedly brought nest material into the box.

Nest material was first observed in a box on Tupper Hill on 11 April. Within the next two weeks activity was observed in other areas. The first eggs were laid about 20 April at two locations near Vineca Pond, one at Tupper Hill, and one at #3 Pond. All of the eggs observed were blue in 2002, and almost all of the nests were constructed mostly of pine needles.

This is the second season with three different box styles. Twenty-nine boxes are standard sized with a round hole. In areas where English Sparrows have been recorded, mainly near the administration building, gatehouse and shop, two other styles are in use. There are seven slot boxes and five U boxes. Both of these designs provide extra space around the entrance hole which does not deter English sparrows, rather allows enough room so that any birds inside the box can escape if need be. Table 1 illustrates the box type and associated use by bluebirds.

English (House) Sparrows and European Starlings are invasive, non-native bird species which were both introduced to the US in the 1800’s. They currently range from coast to coast, and are fierce competitors with native species for cavity style nest sites. Their nests are removed from the nestboxes along the bluebird trail to allow more available nesting sites for bluebirds, which do compete with native species for cavities. During 2002, English sparrows were found to have built their own nests on top of an active tree swallow nests, and were observed in and near a box where two dead fledgling bluebirds were found.

Notes on Standard Box Results: Other species that were observed in these boxes include tree swallow, house wren, black-capped chickadee, white-breasted nuthatch and English sparrow. A red squirrel raised four young in a box near the cedar swamp in early April.

One of the nestboxes at Vineca Vale was observed with 5 blue eggs on 25 April. By 16 May, 9 eggs were observed in the box. On 4 June, 4 week-old hatchlings and 5 eggs were observed. The 5 eggs never hatched, but the hatchlings fledged by 13 June.

Notes on U Box Results: In one instance, two fledglings were believed to be killed by sparrows just before they fledged. English sparrows were removed from four of these houses, along with ten eggs. A house wren nested in a U box late in the season., but tight cramming of wren twigs prevented the observer from determining whether eggs were present.

Notes on Slot Box Results: Of the seven slot boxes, six were used by bluebirds, two by English sparrows (removed), one by starlings (removed), one by house wrens, one by tree swallows and one by black-capped chickadees.

Thirty of the houses have baffles present on the poles. The baffles serve to deter predators that may climb the pole to disturb the nesting birds or feed on the eggs. 64% of the poles without baffles and 57% of those with baffles had bluebird nests in them.

While just about half of the nextboxes face a southerly direction, a small number face in other directions. Table 2 summarizes the use by eastern bluebirds:

Overall Results:

61% of the nestboxes along the bluebird trail had bluebirds construct nests in them during 2002.

Of those, 17 boxes produced eggs and 13 had successful fledglings. Average clutch size was 4 eggs.

On five occasions, bluebirds were displaced from nextboxes by English Sparrows, while on one instance the sparrows were displaced by bluebirds. 14 sparrow nests were removed from 8 boxes, all of which are on or near human activity (walking trail, parking lot, buildings).

Of the 20 pairs of houses present, eight had bluebirds nesting in one and tree swallows in the other, and on four occasions both species were successful (three times bluebirds were successful and the tree swallows were not, and once neither species fledged). The houses are put up in pairs to minimize competition between these two species. Bluebirds moved into boxes the tree swallows had begun nesting in three times, and tree swallows moved into bluebird boxes once. Bluebirds also nested successfully adjacent to house wrens on two occasions.

Adult and immature eastern bluebirds were observed throughout the remainder of 2002 at Tupper Hill.

Note: More than one species can use a nestbox in a season, as the boxes are cleaned out once fledglings leave the nest. At times, birds may begin to build a nest and then not use it.