near the top, with lower limbs 
frequently missing. The under story is 
Vtfiflble, but often well developed. 
Several species of warblers, red-eyed 
vireos, and rose-breasted grosbeaks 
use the canopy. Species of the under¬ 
story are about the same as those 
found in open brush habitat. 
4. The aspen-birch cover type 
of the 1936 burn is now a very diverse 
habitat, with remnants of the former 
forest still represented by snags 
which are used by several hole-nesting 
birds, including flickers, starlings, 
and sparrow hawks. The new forest is 
now large and dense enough to support 
brush species in abundance, and much 
of this area is best assigned to the 
brush type. More advanced areas in 
the burn are now dense enough to sup¬ 
port forest species such as the 
ovenbird. 
5. Swamp and bog forests are 
usually not large enough to maintain 
separate bird faunas, although cross¬ 
bills, purple finches, and olive¬ 
sided flycatchers are often associated 
with the trees of this type. 
6 . Open areas are scattered 
throughout all but the best developed 
climax types, and usually represent 
stages in succession from the xero- 
sere (fig. 12). Bare rocks are common 
on the upper slopes of ridges in 
recently burned areas. The only birds 
known to make use of this habitat are 
some of the migrants or winter visi¬ 
tors, such as nighthawks, horned larks, 
lapl&nd longspurs, and water pipits. 
Grassy areas are used by several spe¬ 
cies of sparrows; sharp-tailed grouse 
depend upon grass mixed with brush; 
and upland brush provides habitat for 
white-throated sparrows and mourning 
warblers. 
7. Riparian brush is well devel¬ 
oped on the shores of Lake Superior 
and on small islands, as well as along 
streams (fig. 2) . The most character¬ 
istic bird of this type is the song 
sparrow. Parula warblers are found 
in dense, high brush or small tree 
habitats, most often near the lake, 
but sometimes along streams. Yellow- 
throats, Canada warblers, redstarts, 
and water thrushes also use this 
habitat. 
8 . Basically two habitats are 
formed by beaver ponds: aquatic, 
used by mallard ducks, black ducks, 
wood ducks, ring-necked ducks, herons, 
and kingfishers; and snag habitat 
for tree swallows, starlings, and 
woodpeckers (figs. 10 and 11). 
Drained ponds present a variety 
of conditions ranging from mud flats 
on which a few shorebirds (solitary 
sandpipers, for instance) are some¬ 
times found, to heavy growths of 
sedges, grasses, and rushes which 
gradually are replaced by riparian 
brush. 
9. Inland lakes and ponds 
probably are not as productive as 
they formerly were, owing to elimi¬ 
nation of a large amount of the 
aquatic vegetation by moose, and 
they may be less suitable for water- 
fowl and marsh birds. Black ducks, 
goldeneyes, mergansers, and loons 
are common inhabitants of these lakes. 
Sheltered harbors present essen¬ 
tially the same habitats as inland 
lakes, except that they are usually 
clearer and more sterile; approxi¬ 
mately the same species inhabit 
both types. 
10. Lake Superior and some of 
the larger bays, especially Siskiwit 
Bay, present shoal and deep reef habi¬ 
tats for deep-water divers such as 
grebes, oldsquaws, and scoters, all 
migrants. 
11. Shoreline habitat is variable 
including wave-washed rocks, small 
islets, and a few beaches, most of 
11 
