The mid-season “switch” was turned on at MABO this past week. We were plodding along at about 25 birds/morning during the first two visits in early to mid-June. This period of the breeding season is known as the adult “superperiod” when adult males and females tend to nests with eggs or young within defined territories. Capture rates tend to be a little lower at this time as there are few young in the area and just a sample of the adults are mistnetted. Young birds appear in numbers around mid-late June and suddenly the site is alive with adults either dispersing or establishing new territories in different spots. Visit three was a perfect example of this as a total of 45 birds were captured during the morning, which included the first wave of youngsters and many new adults banded including the striking Scarlet Tanager pictured above.
This is one of the net sites at Maplewood Bog MAPS station, net number nine of ten. Net nine is located in a wet shrubby clearing within mature deciduous forest. This wet area is actually part of a long and narrow band of flooded shrub habitat within the interior of the forest that connects two wetlands. Northern Waterthrushes seem to use this habitat feature as a sort of highway between territories and foraging areas. We have captured and recaptured a high number of individuals in this location. The photo was taken in late morning when light begins to scatter down to the forest floor but this net site is quite shaded for most of the morning.
The vegetation on the forest floor indicates an uneven canopy closure where enough light passes down to sustain a fairly dense layer of ferns, tree saplings and other herbaceous plants. This type of deciduous forest is preferred by Wood Thrush, Veery and American Redstart among others. Too dense for Cerulean Warblers however, as the singing males recorded here in late May and early June must have opted to look elsewhere for more mature forest with primarily grass/forb understorey.
We captured four waterthrushes, including this adult female in the early stages of a complete moult. The new primary feathers are coming through in the center of the wing, which are noticeably darker and crisper than the adjacent primaries and secondaries feathers from 11-12 months ago. This individual was sexed as female based on the appearance of a waning brood patch, indicating that this was likely an early nester somewhere in the area.
We also banded two new redstarts, including this second-year (SY) male that was captured simultaneously with an adult female in net ten. After-second year males have vivid orange and black plumage while the younger males, born last summer, have an unusually delayed plumage maturation for a warbler. SY males are distinguished from the females by the patchy black feathering around the eyes and bill.
Overall it was a terrific outing and the results certainly give great confidence that the site can yield viable indices of both productivity and survivorship rates for several commonly breeding forest birds of the area. We still have four visits remaining for the MABO site in 2009 as well as a thorough Habitat Structure Assessment of the 20 hectare plot. It is still a bit early to make a final call but I think we can stamp the station with a shiny gold star for its performance thus far. The experience of establishing this and the other two sites will be crucial to setting priorities for expansion of our MAPS network in 2010. Results from visit three to MABO are posted below.
[I should be back to nest profiles and other blog topics tomorrow as I have a ton of content that I want to share with our faithful readers]
Maplewood Bog Results-Visit 3 of 7
New birds banded (36 of 14 species)
Recaptures (9 of 6 species)