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Migrant and Breeding Bird Survey
This page, with some Web links, is intended for viewing on the Web.
For printing, especially because of the wide tables in Appendix A, we suggest using either of these versions: Adobe Acrobat or Microsoft Word. The Adobe Acrobat version can also be viewed on the Web. Adobe Acrobat Reader is available free at www.adobe.com/products/acrobat/readstep2.html
Want to see these birds in action? You can see these birds by following Marj - see mrines.com/Birds/Arlington/
Migrant and Breeding Bird Survey
2002
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Alewife Reservation
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The Friends of Alewife Reservation
Conducted by: David Brown’s Wildlife Services
Carlisle, Mass.
Funded by: The Riverways Small Grants Program
Massachusetts Department of Fisheries, Wildlife and
Environmental Law Enforcement
Table Of Contents
I. The Survey
Total species list…………………………..……………………..page 1
Winter visitors………………………………..………………….page 4
Visitors during breeding season…………………………………page 4
Breeding birds………………………….………………………..page 5
Discussion by order…………………………..………………….page 6
II. Evaluation
Description of the land…………………..…………….………...page 9
General assessment………………………………..…………….page 11
Causes for concern………………...…………………………….page 11
Significant habitats………………………………..……………..page 13
Management recommendations……………………..…………...page 15
Wildlife education……………………………………………….page 15
Appendices
A. Cumulative species list and charts
B. Interpretive commentary
C. Habitat map of Alewife Reservation
D. Cavity users
E. Nest boxes
During the winter of 2001-2 a grant proposal was submitted by the Friends of Alewife Reservation to the Riverways Small Grants Program of the Massachusetts Department of Fisheries, Wildlife and Environmental Law Enforcement to conduct two wildlife inventories in the park, a mammal tracking inventory and a combined migrant and breeding bird survey. The inventories were conducted by David Brown of David Brown’s Wildlife Services, Carlisle, Mass., during the late winter and spring of 2002.
The intent of the surveys was to update information about wildlife populations in the reservation. This information could then be used to evaluate the continuing suitability of the park as an urban wildlife resource, to increase public awareness of the presence of wildlife in an urban area, to inform advocacy for the park and to provide information for advising the Metropolitan District Commission with respect to its management of the resource. Two separate reports have been prepared, one for mammals and one for birds. As each report is intended to stand alone, some information with appropriate modification appears in both studies.
Because funding limitations did not permit separate migrant and breeding bird inventories, it was decided to combine the two into a single study. Whatever the results might lack in completeness, they were expected to provide a sufficiently good view of the bird populations that both reside in the park or otherwise use it as a resource. A total of 89 species of birds were observed in the reservation from late February through June. That total list is presented below, followed by separate tables for winter visitors, visiting species during the breeding season and finally breeding birds.
The following table shows all of 90 species found during the survey. It is ordered according to the evolutionary progression method used in most field guides.
1. Status Codes:
“C”: “Common” describes any bird found on the reservation three or more times in different locations.
“U”: “Uncommon” is used for any species found only once or twice, any second observation occurring at a different location from the first.
“M”: “Migrant” indicates any species found only to be passing through during spring migration.
“W”: “Winter” describes any species present either as a resident or visitor during late winter, when the inventory began, but not during breeding season.
“B”: “Breeding” indicates any species showing territoriality during breeding season.
“V”: “Visitor” describes any species present during breeding season but not believed to be nesting on the reservation. Such a species may be present at other seasons as well.
2. Numbers:
The numbers under Observations correspond to the numbers in the Cumulative Observations list in Appendix A as well as to the circled numbers on the charts included in that appendix. The numbers under Commentary correspond to those same listings and charts as well as to comments in the Interpretive Commentary in Appendix B.
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Double-crested cormorant Great blue heron Black-crowned night heron Mute swan Canada goose Mallard Black Duck Green-winged teal Northern shoveller Wood duck Hooded merganser Common merganser Sharp-shinned hawk Red-tailed hawk Merlin American kestrel Ring-necked pheasant Killdeer Solitary sandpiper American woodcock Least sandpiper Herring gull Greater black-backed gull Ring-billed gull Rock dove Nighthawk Chimney swift Mourning dove Belted kingfisher Common flicker Hairy woodpecker Downy woodpecker Eastern kingbird Eastern phoebe Willow flycatcher Least flycatcher Tree swallow Rough-winged swallow Blue jay American crow Black-capped chickadee Tufted titmouse White-breasted nuthatch Brown creeper House wren Carolina wren Northern mockingbird Gray catbird American robin Wood thrush Ruby-crowned kinglet Cedar waxwing European starling White-eyed vireo Red-eyed vireo Warbling vireo Black and white warbler Northern parula Yellow warbler Wilson's warbler Magnolia warbler Black-throated blue warbler Myrtle warbler Black-throated green warbler Blackburnian warbler Chestnut-sided warbler Blackpoll warbler Prairie warbler Palm warbler Northern waterthrush Common yellowthroat Canada warbler American redstart House sparrow Red-winged blackbird Baltimore oriole Common grackle Brown-headed cowbird Northern cardinal Indigo bunting House finch Common redpoll American goldfinch Savannah sparrow Northern junco Field sparrow White-throated sparrow Lincoln's sparrow Swamp sparrow Song sparrow |
cv cv cv uv cb cb uw uw cw ub uw uw um cv um um cb ub um cb um cv uv uw cb cv cv cb cv cb uv cb cb cb ub um cb um cb cv cb cb cb cb cb ub cb cb cb ub um cb cb um ub cb cb cm cb um cm cm cm um um cm um um cm cm cb um cm cb cb cb cb cb cb um cb uw cb um cw um cw um ub cb
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132 8, 13 39, 43, 44, 49, 77 8, 13, 133, 144 40 79 6 1, 11, 29, 37 7, 12, 30 24, 32, 36, 145, 151 31 5 17 2, 38 35
27, 28, 46, 50, 53 9, 48 72, 78 18, 19, 20, 21, 22, 23, 25, 26 96
4
41
45 124, 125, 146, 147 105 87 98
86 42, 60, 71, 106, 150
119 85 139
95 143, 149 69, 93, 123, 128, 136, 138 83, 99 73, 74, 108, 113, 121 61, 66, 68, 70, 80, 118, 142 109 100, 107, 111, 114 82, 120 54, 58, 62, 63, 67 65, 94 90 130, 137 134 115 52, 57, 64, 88 81, 101, 110, 112 75, 84, 91, 97, 141 126, 135 104, 117, 122, 127
33, 129 76, 140
34
131
3 10 56
148 14, 51, 55, 59
102, 103
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39 133, 144
1, 29 7, 12 32, 145, 151 31
17 2 35
27, 28, 53 48 72, 78 18-26
41
45 124, 125, 146, 147
86 42, 60, 71
119 85 139
95 143 69
73, 74
82 54 65
134 115 52 81 75, 84 126,135 122
33 76
34
131
3
14, 51
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The following listing filters the data in Figure 1 for those species present at one time or another in the winter but not at other seasons.
Although the bird survey was not begun until late February, enough of the winter was left to suggest seasonal visitors. Due to the abnormally warm winter, neither the river nor ponds froze over, allowing use by waterfowl and herons. In addition, one flock of redpolls, visitors from the far North, was observed in riverside alders.
Species Status Observation # Commentary #
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Black Duck Green-winged teal Northern shoveller Hooded merganser Common merganser Ring-billed gull Common redpoll Northern junco White-throated sparrow
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uw uw cw uw uw uw uw cw cw |
6 1, 11, 29, 37 7, 12, 30 31 5 4 3
14, 51, 55, 59
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1, 29 7, 12 31
3
14, 51
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Several species of birds were present during breeding season but are believed to be nesting off-property and visiting the reservation to feed. Great blue herons and black-crowned night herons fall into this category, as do red-tailed hawks.
Species Status Observation # Commentary #
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Double-crested cormorant Great blue heron Black-crowned night heron Mute swan Red-tailed hawk Herring gull Greater black-backed gull Nighthawk Chimney swift Belted kingfisher Hairy woodpecker |
cv cv cv uv cv cv uv cv cv cv uv cv |
132 8, 13 39, 43, 44, 49, 77 8, 13, 133, 144 2, 38
41
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39 133, 144 2
41
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For purposes of the survey a singing or otherwise displaying male of any species located in early June was regarded as sufficient evidence of at least an attempt to breed. If there was any suspicion that the bird was a late migrant, the territory was checked twice to insure that the male was resident. In the case of early nesters where the males may have ceased displaying by early June (e.g. woodcock), earlier evidence of repeated singing or displaying at the same location was also taken as evidence of territoriality and an attempt to breed. A total of 40 species satisfied these criteria and are listed below.
(Interested in information related to breeding birds? See information on Silver Maple Forest. - Note added by webmaster.)
Species Status Observation # Commentary #
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Canada goose Mallard Ring-necked pheasant Killdeer American woodcock Rock dove Mourning dove Common flicker Downy woodpecker Eastern kingbird Eastern phoebe Willow flycatcher Tree swallow Blue jay Black-capped chickadee Tufted titmouse White-breasted nuthatch Brown creeper House wren Carolina wren Northern mockingbird Gray catbird American robin Wood thrush Cedar waxwing European starling Warbling vireo Black and white warbler Yellow warbler Common yellowthroat House sparrow Red-winged blackbird Baltimore oriole Common grackle Brown-headed cowbird Northern cardinal House finch American goldfinch Swamp sparrow Song sparrow |
cb cb cb ub cb cb cb cb cb cb cb ub cb cb cb cb cb cb cb ub cb cb cb ub cb cb cb cb cb cb cb cb cb cb cb cb cb cb ub cb |
40 79 27, 28, 46, 50, 53 9, 48 18, 19, 20, 21, 22, 23, 25, 26
124, 125, 146, 147 87
86 42, 60, 71, 106, 150
119 139
69, 93, 123, 128, 136, 138 83, 99 61, 66, 68, 70, 80, 118, 142 75, 84, 91, 97, 141
33, 129 76, 140
34
10 102, 103
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27, 28, 53 48 18-26
45 124, 125, 146, 147
86 42, 60, 71
119 139
69
75, 84
33 76
34
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Cormorants: At least five double-crested cormorants were persistent visitors to Little Pond in the late spring. One was an adult, the rest immature birds.
Herons: Both great blue and black-crowned night herons were common, especially at the outlet of Little River from Little Pond. No bitterns were detected during the survey.
Waterfowl: 20-30 Canada geese were resident in Little Pond and the river through late winter and into the spring. Most of these were probably non-breeding immature birds. Only two broods of goslings were seen, and those quite small in number. The only other successful breeder appears to be mallard ducks. Two wood ducks were seen flying downriver late in the spring, and what was probably the same pair was seen shortly thereafter in Little Pond at a point when they should have had ducklings if they had been successful at nesting. Given the warm winter, several other species of birds were regular visitors to Little Pond, including two species of merganser, black ducks and as many as nine northern shovellers. A pair of gree-winged teal were persistent at Blair Pond and the river.
Hawks and falcons: A very tame immature red-tailed hawk hunted both sides of the river from late winter into the spring, preying on small rodents in the open areas. All other hawks and falcons observed during the survey were migrants.
Rails: Despite the existence of several small cattail marshes in the reservation, no rails such as Virginias and Soras, present elsewhere in eastern Massachusetts in such habitat, were heard during the survey.
Sandpipers: Two solitary sandpipers and a lone least sandpiper were observed probing the mud bars in both Blair and Perch Pond. It is likely that spotted sandpipers also visit from time to time.
Gulls: Herring gulls were common visitors to Little Pond. One ring-billed gull was also observed during late winter, and a single greater black-backed was observed in late spring, both on the same pond.
Pigeons and doves: Many “rock doves”, as the feral domestic pigeon is called, roosted regularly under the bridge on the Alewife T access road. Mourning doves were common throughout the more open areas of the park.
Owls: Although a great horned owls was reported in the past and may still visit to hunt the small fields at night, none of this species, increasingly common in suburbia, was heard in the park. Few suitable day roosts exist where they can keep out of the wind and conceal themselves from harassing crows. Although there is habitat for screech owls, none were heard. Lack of nest holes probably accounts for this.
Goatsuckers: Nighthawks sometimes nest on the gravel roofs of 3-deckers and hunt flying insects at night over Cambridge. These birds are not hawks, at all, but relatives of whip-poor-wills, getting their name from the habit of “hawking” insects, or capturing them on the wing.
Swifts: Chimney swifts commonly overfly Cambridge during the day, catching flying insects. At night their place is taken by bats while the swifts roost inside the chimneys of some of the older buildings in the area, like the Harvard Smithsonian Observatory. Several were seen flying after insects over Little Pond in late spring.
Kingfishers: Belted kingfishers were observed in late winter and early spring hunting the waters in the park. Another was seen in mid-June over Blair Pond. Apparently a dirt bank used by the birds for breeding was removed and may have discouraged them from nesting in the park.
Woodpeckers: Flickers were heard late winter into spring at the west end of the park around Perch Pond. One hairy woodpecker was seen in very early spring and downies were common throughout the treed areas of the park.
Flycatchers: At least two pairs of very conspicuous kingbirds hunted the river. One pair of phoebes nested at the culvert on Wellington Brook and others probably nested elsewhere. Two singing male willow flycatchers were persistent in the park, one at mid-river and the other at the west end.
Swallows: Tree swallows were common over the waters of the park, while one pair of the less common rough-winged swallow was observed at Blair Pond before nesting season.
Corvids: The calls of common crows were heard constantly in the park. No alarm such as would occur at intrusion of nesting area occurred during the survey, however, suggesting that these birds are breeding off-property. Blue jays were quite common as well in the park.
Titmice, nuthatches and creepers: Black-capped chickadees were quite common in the treed areas of the park throughout the survey. Tufted titmice were less common and white-breasted nuthatches less common yet. Several brown creepers were seen and heard, especially in the early spring.
Wrens: House wrens were singing on both sides of the bikepath in the early spring. Carolina wrens, a species that has been slowly spreading northward, took advantage of the warm winter to extend their range into the Boston area and beyond. Singing males were detected in three separate locations, including one in late spring, suggesting an effort to nest.
Mimic thrushes: Mockingbirds appeared to be nesting in the ornamental shrubbery at the Hill Estates and foraging into the park. Catbirds were abundant in river- and brookside thickets all along the river.
Thrushes: Robins were abundant in late winter and into breeding season, apparently surviving during the colder months on the abundant sumac berries that the park affords. At least one wood thrush was heard singing on territory on both sides of Acorn Park Drive in the Belmont Upland. No hermit thrushes were detected, however. These last prefer a mix of conifer and deciduous trees, the former largely lacking in the reservation.
Kinglets: Only a couple of migrant ruby-crowned kinglets were found in very early to mid-spring, hover-feeding on early insect hatches. Golden-crowned kinglets, which are common winter visitors from the North, were not detected.
Waxwings: Cedar waxwings are very good flycatchers that also like to feed on apple blossoms in the spring. They were first detected in late spring, feeding by the former method near the Little River. Their presence was persistent into late spring. As they are late nesters, it cannot be said for sure that they will breed in the park but this is likely.
Starlings: This introduced species was all too common in the park. Starlings nest very early in cavities, denying these scarce sites to native species.
Vireos: Warbling vireos were singing on territory in several locations in the reservation. Red-eyed vireos arrived rather late with one male singing persistently in large trees near the river at the east end of the park. One singing white-eyed vireo was heard northeast of Perch Pond in suitable nesting habitat for this species; however, it was not heard or seen again.
Wood warblers: Eighteen species of these colorful little migrants were observed in the reservation during the spring. Yellow warblers and common yellowthroats were abundant, their songs being heard in the thickets all along the water system in the park. A Canada warbler was heard twice at the same location at the west end of the park a week apart, suggesting an attempt to breed. The habitat is suitable for this species, but the bird has not been heard since. This does not necessarily mean that the bird is no longer present. Many birds become secretive during the incubation period, singing only when feeling territorial pressure from another male of the same species. As this was the only Canada warbler detected in the survey, it and a mate could be present but with the male maintaining silence. Nevertheless, without additional evidence of presence late in the period, it is classified as an uncommon migrant in the survey.
Blackbirds: Red-winged blackbirds arrived in numbers in March and inhabited every patch of cattail marsh in the park. Common grackles were indeed common in the reservation and cowbirds arrived at the same time as the red wings. These last are nest parasitizers: having adapted eons ago to a nomadic existence following bison herds, they regularly victimize other birds by laying eggs in their nests. Yellow warblers, abundant in the park, are likely foster parents for many cowbird chicks.
Finches: Cardinals were common in the thickets all along the water system in the park in winter as well as spring. This species was rare and local in Massachusetts forty years ago but has spread northward with help of bird feeders, the metropolitan heat island and suburban shrubbery. One flock of common redpolls, visitors from the far North, was observed descending on an alder thicket at mid-river in late winter. A single male indigo bunting sang from an aspen edge in late spring but was not heard again. House finches, a native American bird that was introduced to the east coast from the West, were common near the bikepath, a pair nesting in the air-conditioning plant for the newer Wyeth Building.
Song sparrows were abundant in the brushy wetlands of the park, while house sparrows, a noxious alien species, were common near the bikepath. A number of white-throated sparrows appeared to have overwintered in the park, pushing on with the arrival of spring. Of note was one migrating Lincoln’s sparrow that was located foraging on the ground near Wellington Brook at mid-spring.
A. Description of the land: topography and vegetation. (Please refer to the Habitat Map in Appendix C.)
Alewife Reservation is an urban wild surrounded by industry, heavy-use roadways, office parks and human residences. It is located in the Boston basin, an area that in its geologic history apparently sank under the weight of glacial ice and thereafter accumulated a fine silt that settled out as the final product of outwash from inland glaciers just before their meltwater entered the ocean. Where this silt is saturated by the aquifer, it forms an underlay of clay. Since the end of the last glacial period, however, the area has also been subject to alluvial influence with deposition from periodic flooding that leached out minerals from inland and upland locations, depositing them in a rich black soil over the clay underlay.
Today Alewife Reservation is for the most part floodplain for Little River and Alewife Brook. Historically part of a large marsh abutting Fresh Pond, the area has been progressively filled for development, so that today there is little terrain in the park that has not been disturbed. The Little River, which drains Little Pond, itself fed by Winn Brook and Spy Pond, receives inflow from Blair Pond via Wellington Brook, as well as from a number of sewer discharge conduits. The river was relocated from its meandering natural course and straightened into a channel with steep banks, apparently to prevent flooding and to better serve as a conduit for runoff and sewerage into the Mystic River downstream and ultimately into the ocean. At the east end of the park, Alewife Brook enters the river via a ditch from a culvert at the edge of the park’s boundary near the T-station.
Relocation and channeling of the river in the past has reduced the frequency of flooding but the vegetation types found in the park still reflect a history of periodic inundation. Specifically, the dominant forest type is composed of floodplain species such as silver maple and black willow as well as red maple, all species that can survive total saturation of the soil in which they grow.
A high burm, which at one time elevated a railroad track, runs along the south boundary of the reservation. This burm currently supports a dirt bicycle path as well as some of the few non-floodplain trees present in the reservation, specifically several medium-age scarlet oaks. One large red oak grows in the northwest section of the park, called the “Belmont Uplands” and a number of planted pin oaks, a species not native to this area of New England, line the former Arthur D. Little property on the north bank of the Little River in the middle of the reservation. Otherwise the occurrence of mature oaks in the parks is quite spotty.
Many cherry trees are scattered around the park, including one substantial stand of black cherry in the woods near the northeast shore of Little Pond. These were probably escapes from homesteading in earlier times since these trees, valued as furniture wood and for tool handles, were often planted around residences as a money crop.
Apple trees are also frequently found in the park, mostly at its western end, apparently relict from an orchard that existed in the area many years ago. As these trees are no longer cultivated, they are not sprayed, creating an attractant to insects and to the birds that feed on them.
Aspen, or “poplar” as the two native species are called in New England, are found in several areas of the park. The most extensive stand is at the eastern end of the reservation south of the river. However another small grove exists south of Perch Pond and a third at the northwest corner of Yates Pond, with many individual trees scattered around the park. These trees are regarded as successional, creating shade under which they themselves cannot reproduce and thus preparing the way for more shade tolerant species to follow. The presence of two pure stands in the floodplain is probably a function of the frustration of natural periodic flooding of the area, a factor that has allowed this species to make advances in the more open areas of the park, especially at its eastern end. The recent residence of beavers in the park has resulted in cutting of many of these trees, a favorite feed species for these large rodents. It is possible that this feeding activity may stabilize the aspen groves so that the successional process is short-circuited, ironically perpetuating the presence of aspen groves in the park.
Many other species of trees are present in small numbers on the reservation. Norway maples and boxelders, neither native to the region, are probably escapes from the cultivated trees planted along city streets to replace the elms that were devastated by the Dutch elm blight. A number of fairly mature ashes can also be found scattered around the floodplain.
Interestingly, few conifers exist in the park. The only ones that are present were planted as landscaping on the property of abutters and are so scarce that they do not serve as a significant habitat for species that prefer this forest type. In winter great horned owls, the most common suburban owl, depend on dense conifers for roosting sites, out of the wind and concealed from harassing crows. Lack of such trees means that these owls must visit from other areas in order to prey on the abundant rabbit and vole populations in the park’s fields.
At most, the western sections of the park can be described as open woodland; nowhere except in the extreme northwest portion is there anything like a closed canopy. The eastern section is more open and marshy, with the exception of the near-monoculture of aspens in one extensive grove.
In the more wooded sections of the park undergrowth varies with sunlight at the surface. Under the silver maples in the northwest section there is relatively little, with bare alluvial soil visible under dead leaf cover. In more open woodlands in the western part, are a variety of bushy species like honeysuckle, with shrub dogwoods and European buckthorn, an invasive, proliferating along the river. Pussy willows and alder grow in the marshy areas at mid-river. Sumac genets are very common everywhere in the park, in some places amounting to monocultural growth with individuals occasionally growing to the stature of trees.
Many small cattail marshes exist especially in the wet impoundments on both sides of Little River in the middle of the park. However, another exists along the northeast shore of Little Pond and a third at the west margin of Yates Pond. All these marshes are under siege by invasives, particularly purple loosestrife. Pure stands of giant reed (fragmites) and Japanese knotweed are spreading in the bottomlands, with latter concentrated at the east end of the park and along the burm south of the river.
B. General assessment
The area surrounding Alewife Brook has been visited by birders and other naturalists since at least the days of William Brewster, the first ornithologist in the history of the Commonwealth. In his day the area was a large marsh and swamp associated with Fresh Pond to the south. Since then the area has been cut over, carved away and filled for industry and residence, a process that continues to this day. In addition the waterways have been altered so that Alewife Brook has been reduced to a ditch emerging from a culvert and running only a couple of hundred yards before entering the Little River, itself rechannelled from its natural meandering course where it once flooded an extensive wetland. The reservation proper is only 115 acres, but abutting private property on the northwest side of the park, still in more or less natural condition, increases the size of the “greater Alewife natural area” by another 25 acres or so.
Despite the small size of the park the survey found Alewife Reservation and its abutting natural acreage to be a vibrant and valuable bird resource with a total of 89 species noted during late winter, spring and early summer. Anecdotal and published reports put the total number of species possible in the reservation even higher. It is likely that persistent observation year-round would push the total number of species, resident and migrating, to well over 100.
The reservation’s attractiveness to birds results from both its variety of habitats, described above, as well as its location. In spring (and presumably in fall as well) migrant birds passing in the night over the relentlessly urbanized Boston/Cambridge area need somewhere to stop, with habitat that will permit them to rest, feed and replenish energy before moving on. Hence the well-known concentration of bird life at local cemeteries like Mt. Auburn. The varied habitats of Alewife, large trees, swamp, brushy borders, fields, wetlands, river and pond provide a useful stop-over for a correspondingly diverse selection of migrant species. Alewife’s wildness, as opposed to more cultivated and urbanized parks and cemeteries, makes it especially useful for this purpose.
Since Alewife has no extensive forest, it is not surprising that canopy species like scarlet tanagers and wood pewees were not recorded during the survey. Nor were ovenbirds or hermit thrushes found, ground-nesting species that seems to require extensive woodlands with little intrusion by dogs. In former times when there were more extensive woodlands with mixed composition, all these species would probably have been present. Instead, Alewife supports bird species that favor more open, brushy and wet habitats.
C. Causes for concern
1. Feral cats. At least four apparently feral cats currently hunt the park south of Little River. To a certain extent they mimic natural predation in the absence of bobcats. However, the fact that two were seen consorting suggests a colonial situation in which they can become numerous, resulting in a serious effect on ground nesting birds like woodcock. Hopefully the recently arrived coyote(s) may have some effect on the feral cat population. The sign of coyote was limited to north of the river while feral cats were on the south side, either as a function of coyote presence or the relative isolation of the north side, or both. If coyote predation does not control cat numbers, active measures may be needed.
2. Carp. An abundant population of carp was observed in Little Pond and Little River. Introduced from Asia for the benefit of sportsmen, these fish are bottom feeders that plow through the muck in the riverbed, searching for organisms to eat, eliminating vegetation and contributing to the turbidity of the water in the process. Carp grow quickly to very large size, the reason for their attractiveness to fishermen. However, their size provides immunity from predation by birds as large, even, as great blue herons. The only native predator that could serve as an effective control of the numbers of this fish is the bald eagle, a species too scarce at the moment to have any impact. To what extent the current condition of the water supports native fish of smaller size, which serve as prey for herons, mergansers and ospreys and to what extent their apparent decline is a function of being displaced by the carp is a reasonable area for further study.
3. Lack of anurans. The absence of singing frogs or toads from the park is ominous. These species collectively, the frogs and toads themselves as well as their tadpoles and eggs represent a significant component of the prey base for many carnivorous birds and mammals. The channeling of the river eliminated much emergent vegetation upon which several species depend, but degraded water quality may also be a factor
(Interested in information related to lack of anurans? See information on vernal pools. - Note added by webmaster.)
4. Alien bird species:
House sparrows were introduced from England early in our country’s history and have become thoroughly naturalized. Other species introduced from the old world held to their former migratory patterns, flew southeastward and perished at sea. But house sparrows, or “English sparrows” as they are also called, are non-migratory and therefore adapted well to America. They are aggressive cavity nesters that displace native species, even to the point of piercing the eggs of competing native species. Very adaptable to urban areas, house sparrows are fairly common along the bike path in the reservation. Any bird boxes erected in the park should be actively monitored to remove the nests and eggs of this species, should it take residence.
Starlings, also introduced from England, are non-migratory, nest in cavities and are very early and aggressive nesters, denying these sites to native birds. As of late May fledged starlings were already being observed in the reservation. The cautions recommended for house sparrows with respect to bird boxes apply to this species as well.
House finches. Although this attractive species is native to North America, it is not native to the East Coast. However, since its introduction near New York City, it has spread rapidly. Similar to house sparrows in its nesting habits and adaptability to urban settings (one pair is nesting in the air conditioning unit at the new Wyeth building), it is at least a native North American species, whatever its effect on local bird populations.
Mute swans are naturalized escapees from estates to which they were brought from Europe as ornaments because of their long graceful neck. This exceptionally long neck allows them to root out aquatic vegetation at greater depth than native waterfowl, denying them food, and these swans have a reputation for hostility toward natives in their nesting territory. For both these reasons the mute swam is in disrepute with game managers. Its initial nesting in New England has been mostly confined to coastal areas. A pair of this species were sighted persistently in the river and Little Pond in late spring. They did not appear to be attending a nest, but they should be monitored against that possibility in the future.
D. Significant habitats.
1. Apple trees. Apparently escapes from a former orchard in the area, many apple trees dot the reservation, including one grove of crab apples adjacent to Wellington Brook and the Hill Estates (formerly Hill Farm). Unsprayed apple trees are magnets for migrating and resident birds. Cedar waxwings feed on the petal blossoms; orioles search them for insects, and many species of wood warblers gravitate to them during migration for the insects that the blossoming trees generate.
2. Old trees with cavities. Approximately 50 species of birds and mammals either use or depend upon natural cavities in old or dead trees for nesting, denning or roosting sites (See Appendix D). There is a general trend toward older trees in metropolitan parks, none having been lumbered in living memory. Unfortunately Alewife Reservation has relatively little forest cover, most being in adjacent private land and much of that vulnerable to development. The few old black willows and a scattering of other ancient trees within the park are, therefore, a scarce and valuable resource. Properly constructed, maintained and monitored bird boxes could assuage the scarcity of nest holes in old trees in the park, providing nest sites for wood ducks, screech owls and kestrels, none of which were confirmed as nesting in the reservation despite favorable feeding habitat.
4. Aspen groves. Large toothed and quaking aspens are spotted around the reservation with the most notable grove on the south bank of Little River toward the east end of the park. Being northern species, these trees bud very early in the spring, generating a corresponding insect hatch that in turn attracts migrating birds, particularly wood warblers. Palm warblers and myrtle warblers, among the earliest spring migrants, found this grove in numbers in April followed by Nashville warblers, black and white warblers, magnolia warblers and a blackburnian warbler. Goldfinches feed on both seeds and insects in the canopy and a lone indigo bunting was heard singing from the edge of the grove in late May.
Aspens are normally thought of as temporary, successional trees, creating shade for other trees but unable to regenerate, themselves, in their own shade. Aspens have marched into the Little River wetland apparently as a result of the channeling of the river that prevented the periodic flooding that would keep them back. Since they are the favored feed tree of beavers, they are clearly the attraction for the ones currently residing in the park. It remains to be seen whether beaver predation on these trees will result, ironically, in an equilibrium and prolonged presence of both species, aspen and beaver, in the park.
5. Small fields. A number of grassy areas exist in the reservation. Two are on either side of the river at the east end of the park, a third just west of ADL, a fourth complex on the north bank toward the west end of the river and a fifth at the old skating rink site in the extreme northwest corner of the park. In addition to their value for mammals, all the sites mentioned held displaying male woodcocks early in the spring. The abundant vole and rabbit populations in them serve as a prey base for red-tailed hawks, regularly seen surveying them, and probably owls during the night as well. The edges of such fields tend to respond to the abundant sunlight they afford by growing up to dense brush, valuable to abundant species like song sparrows as well as to locally rare ones like the lone white-eyed vireo heard during the inventory period.
It is widely recognized at this juncture that grasslands are a disappearing resource in the Commonwealth as they either succeed back to forest or are eliminated by development. Their increasing scarcity makes the five small plots at Alewife Reservation significant habitats.
6. Dense brushy thickets with brambles. These sites, which provide cover for wildlife, are abundant in Alewife and account for the large number of song sparrows in the park. The presence of blackberry canes effectively prevents human intrusion into many areas. Since dogs generally accompany humans, they, too, are kept more or less away from many areas.
7. Water and shoreline. Water in Little Pond and Little River as well as in swamp and marsh areas benefits many species of birds. Great blue herons hunt the river and pond edges as long as there is open water; black-crowned night herons arrive in early spring and hunt Perch Pond and river outlet from Little Pond. Several species of shorebirds have been seen picking over the mudflats in Perch and Blair Ponds; tree swallows harvest the insect hatches over the river and ponds. Kingbirds and phoebes, as well as cedar waxwings and willow flycatchers, also feed on flying insects over water. Wood ducks visited the river in spring; green-winged teal overwintered at Blair and Perch Ponds; mallards are nesting in the river; several species of ducks were present in Little Pond in late winter including hooded mergansers and northern shovellers. Twenty to thirty Canada geese also wintered in the river and pond. Both yellow warblers and common yellowthroats feed and nest in riverside thickets; northern waterthrushes were heard along Wellington Brook through most of the spring.
8. Contiguous wild land. Different species of wild animals have different comfort levels as far as minimum acreage is concerned. As contiguous wild land is cut up or encroached upon, species begin to drop away. The exact threshold is hard to fix, varying with acreage, level of human and pet intrusion and richness of habitat as well as species and individual preference. Unfortunately one tends to discover the threshold for a particular animal only after it has disappeared. The largest block of more or less unbroken acreage, at the moment at least, is north of the river and west of ADL, in an area loosely referred to as the “Belmont Uplands”. Isolated from frequent visitation by barriers of river, pond and highway and broken only by Acorn Park Drive, the access road to ADL, it provides a large block of contiguous green space with varied habitat: floodplain forest, marsh, swamp and shoreline and field. One of its greatest values to wildlife is its space, acreage that defends the unpredictable threshold of abandonment by wild species. Unfortunately this area, a large part of which is privately held, is on the verge of development, which at the very least will break up and reduce critical green space as well as radically increase human intrusion in sensitive habitats such as the woodcock lek in a field at the edge of the park property.
E. Management recommendations
Most of the recommendations for wildlife education opportunities that were discussed in the companion Mammal Tracking Survey apply as well to birds. Specifically:
In Appendix A are all the bird observations recorded during the survey, listed in chronological order. Charts of the location of each observation follow, the circled numbers corresponding to the observation numbers in the listing.
It should be noted that not every observation of any given species was recorded. Very common and expected species such as blue jays, house sparrows, starlings, robins, catbirds, mourning doves and so forth were not listed at all, and other fairly common and expected birds, such as red-winged blackbirds, were listed only upon first observation or upon being found in a new area of the park.
This chart shows the major terrain features and habitat regions of the park.
This is a list of birds that either use or depend on cavities in either live trees or standing deadwood for nesting or roosting.
This appendix contains a discussion of nest box construction, placement and maintenance to improve the availability in the park of sites for cavity nesters.
Appendix A: Cumulative observations list |
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|
# |
Date |
Location |
Species |
No. Sex/age |
Behavior |
Habitat |
|
1 |
2/7 |
Blair Pond |
Green-winged teal |
4 m/f |
on water |
small, shallow pond |
|
2 |
2/7 |
E corner ADL parking Iot |
Red-tailed hawk |
1 imm |
perched low, next to river |
Grassy ground at river edge |
|
3 |
2/16 |
viewpoint across ft ADL |
Redpolls |
20 m/f |
feeding on alder catkins |
Riverside alders |
|
4 |
2/16 |
Little Pond |
Ring-billed gull |
1 adult |
flying over wafer |
on large pond |
|
5 |
2/16 |
Little Pond |
Common merganser |
2 f |
resting on water, preening |
on large pond |
|
6 |
2/16 |
Little Pond |
Black duck |
2 ad |
paddling |
near shore of pond |
|
7 |
2/26 |
Little Pond |
Northern shoveller |
7 m/f |
on water, feeding |
on large pond, away fr shore |
|
8 |
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