Some City Birds Are Changing Their Tune

The ecology of urban ecosystems profoundly influences the plants and animals that live in and near cities, and even changes how birds sing – to read more about this, see here:


The Spruce Street Swamps

If you were to walk down Spruce Street in West Philadelphia today, going westward from the University of Pennsylvania, you would see a lot of houses, and a lot of pavement – concrete sidewalk, asphalt streets, building materials of numerous variety, all covering the ground that lies beneath.  There are, of course, also many trees you would walk by – the magnificent Franklinia at the southeast corner of 42d and Spruce is a classic, and directly across from it, at the southwest corner of that same set of cross streets, is a large and majestic, though wildly trimmed, Paulownia.  Also along that south side of the street is a row of houses dating from the 1880s, and they are guarded out front by their regularly spaced and by now quite large squadron of Japanese maples.

And the north side of the street is not lacking for lignin either – there is an enormous white oak in the churchyard there, on the north side of the street, in the same block that includes the Sadie Alexander School, between 42d and 43d Streets, north of Spruce.  In that yard are also two pines – one an eastern white pine (Pinus strobus) and the other a Himalayan pine (Pinus wallichiana) – paired up against each other, along 42d Street, ready to be compared.  These are two tree species that I’d found difficult to differentiate until I came across these two examples right next to each other, set up like a coniferous teaching collection, just waiting for some comparative taxonomy.  Both of these species are five needle pines (pine trees’ needles, of all pine species, are arranged in clusters, called fascicles, and all pines either have five needles, or two-or-three needles), and those needles are somewhat light in both strobus and wallichiana, and both of them have rough, platey bark, and so it’s not easy to tell them apart, until you see them right next to each other, as one does here at 42d and Spruce.  Here you can see that the needles of the Himalayan pine are longer, and more droopy (“pendulant”, one might say), as compared to the white pine’s needles, which are more upright, and look, to me, a bit like little fireworks’ bursts, as compared to the more hanging tresses of the Himalayan pine.  (also, as my friend and botanical compadre Doug Goldman has reminded me, wallichiana cones are much larger than those of strobus)  And if you go and take a look at them, and look at their bark, you’ll see by the horizontal arrangement of holes on the wallichiana, and the absence of such holes in the strobus, that sapsuckers (a kind of woodpecker) are able to tell these two species apart.  Both of them are quite attractive trees, and both do quite well in Philadelphia, and I hadn’t realized how common the Himalayan pine is here until I learned to tell it apart from its cousin, and these two trees at 42d and Spruce were quite helpful for getting me to learn how to do that.  (to read more about this block, see here: )

And so, I guess I’ve made the point quite well that there are quite a few trees along Spruce Street here – now, on with the peripateticism…

As we are walking along, heading west, if we were to look back towards Penn (fondly, one hopes), we’ll see the street sloping down, and we’ll realize that our legs might be a little sore from having been walking uphill to get where we are, and that we most likely broke a sweat (we’d definitely be sweating on a day with weather like we’ve been having recently), and then as we turn around, facing our goal of heading west, then we see that there’s still a bit of hill ahead of us – up to 45th Street, where there is a rise that we can stand on top of like a little king of the world, and then, towards 46th Street, after we cross the rise, the ground angles downwards.

If we were here a hundred and twenty years ago, this would have looked quite different, though some of the angles would have still been similar.  In the early 1890s, the surfaces we see now would not have been here, not the sidewalks, nor the asphalt.  Though this dip was here, it was through a very different landscape – it was a different world back then, and one we know about in surprising detail, due to the wanderings of Alexander MacElwee, among other sources.

The go-to book to learn about botanists of Philadelphia up until the 20th century is John Harshberger’s The Botanists of Philadelphia and Their Work, and the following biographical information is from that book –

Alexander MacElwee was born in Scotland in 1869 to a relatively large family (he was one of eleven children).  Alexander was the eldest of the younger MacElwees, and he went to school before finally getting to go to work at the age of twelve years old.  After a couple of years of working in Glasgow, he went to join his parents who had already arrived here in the new world of Philadelphia.  His first job, this was in 1883, was working in a garden at 39th and Walnut – the garden was owned by A. J. Drexel (see the 1895 map here:, who would go on to start up the Drexel Institute of Art, Science, and Industry, which would then go on to become Drexel University in west Philadelphia, just north of Penn. (NB: that location is now occupied by Penn’s Fels Institute of Government – do any of the plants now there date to MacElwee’s time?  I don’t know)

MacElwee worked in Drexel’s garden, and also began to learn formal botany by going to meetings of the Botanical Section of the Academy of Natural Sciences, and after a few years, he moved up, both geographically and hierarchically – he went to work at Hugh Graham’s nursery, right near Girard College in North Philadelphia .  This nursery was at 18th and Thompson, and Mr. MacElwee “had charge of several houses, one entirely of ferns, another of palms, etc (Harshberger, 1899).  [The Graham Nurseries was at the NW corner, caddy corner across from St. Joe’s, as may be seen on G. M. Hopkin’s 1875 map of Philadelphia – incidentally, as is noted in his obituary in volume 38 of the magazine “Christian Nation”, Hugh Graham worked as department manager for John Wanamaker prior to becoming a somewhat major Philadelphia florist (he also had “large nurseries at Logan Station, near Philadelphia” [as of 1895, they were at 13th and Loudon, bounded on the west side by Old York Rd]); Mr. Graham died of pneumonia on the 14th of March 1903.]

But MacElwee was to move on soon again – to work as an apprentice bricklayer for a time (during which he had the spare time to expand his knowledge of natural history by field work and by working with botanical museum collections), and then on to work in John Wanamaker’s garden in Jenkintown, and then on to the College of Pharmacy (now the University of the Sciences in Philadelphia) to work with their museum collections of dried, pressed plants.  And as he worked, he learned, and in 1894 he went to work for the University of Pennsylvania laying out the Botanical Garden that was being planned.

As we learn from MacElwee’s obituary in Bartonia (the journal of the Philadelphia Botanical Club), No. 9, 1925-26, “Mac” continued to work at a number of places, until 1917 when he “was appointed landscape gardener by the park commissioners of Philadelphia.”  His dream was to have an arboretum, and he worked assiduously towards that end – traveling to the Arnold Arboretum, to the Brooklyn Botanical Garden, to the Seed and Plant Introduction Service in Washington, DC.  He gathered an immense number of plants and brought them back home to propagate – “thousands of the rarer rhododendrons, flowering cherries, barberries, hydrangeas, hollies, lilacs, roses, crab apples, oaks, loniceras, etc., etc., were started in the Park nurseries, intended for the Arboretum.  Now that the master spirit has gone the project of the Arboretum has rested almost inactive, but these young trees and shrubs remain and form a nucleus from which MacElwee’s dream should be developed.”  Mr. MacElwee passed away on the 23d of January 1923.

While he was alive, Alexander MacElwee, like most botanists, liked to be on the go – he was like this with respect to his working life, as we have seen in the above paragraphs, and also with respect to his day to day ways and wanderings, which he diligently recorded with pencil, pen and paper.  And from these writings of his perambulations, we can learn what was here before.

MacElwee’s field notes are in the archives of the Academy of Natural Sciences, and going through them, with the help of the Academy’s archivists, Clare Flemming and Megan Gibes, we see a man who liked to walk, and they also show with great detail the places where he walked.

Like 46th and Spruce, for example, the dip in the road that I mentioned above.  MacElwee walked near there, in the early 1890s, and after he got home, he wrote the following:

“March 27, 1893
This eve, when coming home from work through the marshy hollow south of Walnut St. and west of 46th Street, I found some boys fishing for tadpoles.  I was not aware that one could find tadpoles this early in the season.  These I seen were of good size, having heads about 1/2 long, and tail twice as long.  The boys caught them by dipping up a large can of water out of the stream and then pouring the water out slowly and catching the tadpoles as they appeared and putting them into another which contained their captives.  One of the boys said he was going to raise them in an aquarium.”

(the underlining is from the original)

This isn’t the only mention he makes of this area – in an entry for the 1st April  1893, he mentions finding Alnus (alder), in flower, in a marsh west of 45thSt. and between Walnut and Spruce.  A few days later, on the 6th of April 1893, he came across “A large spreading tree in the hollow 46 + Chestnut”, at the southwest corner, that was “Probably Acer saccharinum” (i.e., silver maple – a tree still commonly seen throughout west Philadelphia as a street, yard, and park tree – but on its own, without humans planting it, it’s generally a wetland tree).

A bit later on in the year, on the 17th of June of 1893, Alexander MacElwee took a walk and came across a shrub of the Eastern Wahoo (Euonymus atropurpureus) “in front of farm house about 47 and Pine St.”, and some American elderberry (Sambucus canadensis) in the “Spruce St. Swamp”,. as he called it.  That same day (the 17th of June, that is), and right nearby, he saw an American hornbean (Carpinus carolinianus) “At spring W. side of Spruce St. swamp”.

If we look at Ida Keller and Stewardson Brown’s Handbook of the Flora of Philadelphia (published in 1905), we see a couple of entries that also let us know that this area was a wet one, such as –

“Sagittaria Engelmannia …Shallow water.  Summer.
Philadelphia – 46th and Spruce Streets”

This entry is quite likely based on a collection that is in the herbarium of the Department of Botany of the Academy of Natural Sciences, here in Philadelphia – it is a specimen labeled Sagittaria latifolia (the current name of this plant that Keller and Brown list under S. engelmanniana), and the label’s locality data says “stream near 46th and Spruce Sts” and is dated the 4th of September 1887.  [this also indicates are reasonably high quality wetland was there at the time – in Small et al’s 1994 paper in Restoration Ecology, “A Macrophyte-Based Rapid Biosurvey of Stream Water Quality: Restoration at the Watershed Scale”, they report Sagitaria latifolia from nearly 27% of the high quality streams they surveyed in the Chesapeake Bay watershed, yet not at all from their low quality stream sites]

Another entry in Keller and Brown’s flora locates a wet area here – a record of Salix alba (white willow), which prefers “Moist soil” (as Keller and Brown note) is also there, noted as being at 46th and Chestnut.

However, this area wasn’t all swamp and wetland – there would have been some drier, upland areas, too, as is indicated by another collection by Alexander McElwee, of Castanea dentata, from 46th and Spruce, this one from the 3d of July 1887 (and also currently accessioned in the Academy’s herbarium).  Castanea dentata, or the American chestnut, as it is more commonly known, isn’t one to grow in swamps around here (though up in New England I would see it sometimes in moist areas), and so its presence, as indicated by this collection, in turn indicates that some areas were up above the wet – it wasn’t all swamp and marshes.

And so from these notes from these fieldbooks in the Academy’s archives, and from collections in the Academy’s botany department, and from Ida Keller and Stewardson Brown’s book, we see that up until the end of the 19th century this was an open area, the area nearby to 46th and Spruce, with farmhouses, and wetlands – streams, hollows, and marshes.  And it went on, this open area, out south and westward:

“On one of the vacant fields near 50 + Baltimore Ave. is a large spot where sods had been cut off last spring.  I notice that all this spot (and it is quite extensive) a thick crop of Ambrosia artemisaefolia (roman wormwood) has sprung.  It is rather remarkable.  This land has not I suppose been turned under by the plough for years.  There are one or two other things among it, but the Ambrosia predominates where the sod has been cut off. growing densely to a uniform height of 7 or 8 inches.  In many cultivated fields further on  I noticed plenty of it.  But it is not so remarkable in such situations.”

And as further evidence of open areas in this part of town, in Keller and Brown’s 1905 Flora of Philadelphia and Vicinity, they list Centaurea nigra (knapweed) as having a habitat of “Waste places” and a locality of “48th and Baltimore”.

There were also more wet areas, going west – Black Oak Park (now called Malcolm X Park) had some, out at 51st and Pine (the park extends down to 52d and Larchwood), as is shown by the entries in the Plants of Pennsylvania database for Carex annectens and Cyperus odaratus, with locality data identified as “Black Oak Park” – both of these are facultative wetland plants (that is, they can grow in wet areas, but don’t require it, and can grow in drier spots), and so while they don’t indicate absolutely a wetland, they do imply some moist area was there, in what is now a dry city park, still with trees throughout its environs, though, and even at least one that is a wetland tree.  At the northern boundary of the park, between 51st and 52d Streets along Pine Street, there is a magnificent blackgum tree (Nyssa sylvatica), a tree also known as the tupelo –  a tree that on its own is a wetland plant, but also does pretty well as a tree in drier areas (like a city street or park), and it stands tall in the middle of west Philadelphia, at the northern border of Malcolm X Park.

By the 1920s, at least, this park was pretty dry, as is indicated by the following photos:

Black Oak Park (now called Malcolm X Park) – entrance – 51st and Larchwood; 16th of May, 1927 – image from

Black Oak Park (now called Malcolm X Park) – 52nd and Pine Streets – 28th of March 1921 – image from

These scattered collections and references illustrate just how much of west Philadelphia had wetlands and hills, and wetland plants and upland plants, and farms and farmhouses, too – up until at least 1910, this area west of 46th Street was still open, as is indicated by G. W. Bromley’s map (accessible here: ).  And if one were to look at Mr. Bromley’s 1895 map, a map that is also available at the aforementioned address, one would see a stream running up north along 46th Street, and by looking back a little further in time, for example to Samuel Smedley’s 1862 map, one would see that this stream was a tributary of Mill Creek, which flowed into the Schuylkill after stopping for a break at a mill pond at what is now Clark Park (a large park that spreads south from 42d and Baltimore Avenue). [and there was “Desintegrated Feldspar.  Kaolin.” here as well: “Feldspar in a state of decomposition exists on the canal road, and on Mill creek, near the Baltimore turnpike…” (Isaac Lea, “An Account of the Minerals at present known to exist in the vicinity of Philadelphia”, Vol. 1, Journal of the Academy of Natural Sciences of Philadelphia, December of 1818)]

These areas, while now paved over, filled in, and leveled, still have parks and yards and street trees – they have changed and been changed, been paved over and built upon, but as always, life remains and plants grow, in different environments than before, and often, though not always, with different plants than were there before, but marking, in everlasting flux, the perpetually changing times the city lives through, always and in all ways, and endlessly transformed.

And of course it is not only the plants and the landscape that change, but the animals as well, such as the birds, as is noted in George Nitzsche’s 1917 article in the Penn Gazette (“Bring Song Birds Back to Campus!”), where he notes a list of 72 birds compiled in 1906 by Cornelius Weygandt (Professor of English at Penn) and his compatriots, and comments on the changes in the avifauna, from the ten years prior, to his time then – he notes one change especially: “The English sparrow has invaded, in greater numbers each year, our suburbs, our public parks and squares, and other little breathing places in great cities.”  This was due in part to expanding urbanization but also to the introduction of this European species to the new world, an introduction that was the largest here in Philadelphia: “This year (1869) witnessed the importation, in one lot, of a thousand Sparrows by the city government of Philadelphia ; and this probably Is the largest single importation of Sparrows ever made to this country.”  (Walter Barrows, 1889, “The English Sparrow in North America Especially Its Relations to Agriculture”)  And so the changes wrought come from many causes.

Of course, while some things do change, others don’t so much, and so I would like to close with a final quote from Alexander MacElwee, from 1893:

“Requisites for the Botanist and Entomologist while on the march.

1:- Money. This is an indispensable article and mainly used for carfare, ferries, etc

2:- Provisions. This may consist of a good lunch of sandwich.  pastry or extra side dishes can be dispensed with.  It is surprising how delicious a couple of slices of bread and butter with a little cheese is after tramping several miles in the country, washed down with a draught of water from a spring of wayside creek.”

Plus ça change…

To read more about West Philadelphia’s ecological history, see here:

Cedar Grove

There used to be a train station, in the lower northeast of Philadelphia, called Cedar Grove.  It was on Tabor Ave, just a bit southwest of Godfrey Ave, and was on the Frankford spur of the train line that goes to Fox Chase, which is in a bit farther part of the northeast of Philadelphia.  This spur went just about all the way to Frankford Ave, ending at a terminus between Unity and Sellers Streets.  It was a train line that carried freight and also passengers – starting in the late 19th century, it lasted well into the 20th century, going behind the Sears on the Boulevard, along the eastern edge of Northwood Park, and among the houses of heavily populated Frankford.

It also traveled through Cedar Grove.  This was the name of the neighborhood, as well as the train station, and up through the early part of the 20th century, it had open marshes and thickets, and forests with spring wildflowers, and wild flocks of birds filling the sky.

Cedar Grove is just to the east of Tacony Creek and just above the Boulevard, and in the early part of the 20th century it was quite unbuilt.  There were woods there, with beeches and oaks, and poplars and sweetgum and ash trees and sassafras, too, all growing there among each other.  In the spring there were anemones and partridge berries on the forest floor – and hayscented fern was there, as was the trout lily, one of the beautiful wildflowers of the spring, which would’ve come up year after year alongside the mayflower that was there, neighboring side by side with the bellwort (Uvularia sessilifolia) and jack in the pulpits.

Another fern, royal fern, would’ve grown in low wet areas of the woods, and yet another fern, interrupted fern would’ve been a bit higher up.  Royal fern, whose latin name is Osmunda regalis, is in the same genus as the interrupted fern, Osmunda claytoniana.  The interrupted fern, however, likes it a little bit drier than its wetland cousin, and so would’ve been in areas a bit drier – upland and underneath the trees, growing along with and near the wood sedge that would’ve dotted the ground up there.

Dwarf ginseng was also in the woods of Cedar Grove, on the ground, growing among the willow oaks, and poison ivy scrambled there, too.  Pinxter, the azalea with its wild pink flowers, would’ve been a bright beacon in the forest of the early spring.

Beneath the beeches and the oaks were also Dutchman’s pipes, a plant also commonly called by its Latin name, Monotropa.  This is a parasitic plant, it doesn’t make its own sugar, it isn’t green, it doesn’t photosynthesize – it eats sugar that is carried through mycorrhizal fungi, this achlorophyllous plant parasitizing the fungus that in turn has gotten its sugar from a plant with which it is mutualistically symbiotic.

In addition to these forests, there were wide open flats, somewhat wet, in Cedar Grove, with sheep laurel and blueberries, and purple milkwort (Polygala sanguinea), too.  Swamp white oak and black willows made little canopies here and there in these wet areas, as woolgrass (Scirpus cyperinus) nodded in the breeze nearby, bobbing along with the rustling of the narrow leaved and the wide leaved cattails.  Swamp milkweed (Asclepias incarnata) attracted the butterflies, and close to the ground, trailing lightly and low, was the cranberry (Vaccinium macrocarpon).

And there were birds – enormous flocks of blackbirds flew above the flats.   And in the woods Eastern Towhees (which also used to be called, colloquially, “chewinks”) scratched and picked among the leaves, loudly and boldly, with White-throated Sparrows following behind them, picking through their trails.  American Kestrels (also known as sparrow hawks, back in the early 20th century) cruised above the long flat fields of Cedar Grove, and Ovenbirds walked among the forest trees, occasionally flying up to sit in a tree’s branch and sing.

Meadowlarks, now rarely seen in Frankford, used to be in Cedar Grove year round – in the middle of December, in flocks numbering to more than 25, they’d get flushed by a train going by and fly through the air.  And the Winter Wren was out along the train tracks, too, in the icy cold, a little chilled hobo out there in the sleet and snow.

So how do we know all this?  How can I say with such detail what was living and growing in Cedar Grove in the early 20th century, when I wasn’t there and wasn’t until many decades later?  Well, one can reconstruct former ecologies, one can estimate historic plant and animal communities, by knowing habitats of plants and animals, and figuring out, based on climate and soil and hydrology what the habitat of the site would have been in the past, and then, building from that information, one can construct a vision as to what would have been there in the past.  That’s one way to do it, and for most places in the world, that’s really the best you can do.

However, in Philadelphia, we very often have another way to do this – here, we have extensive written records and museum collections, and it’s amazing the level of detail available, documenting what has lived here before.  One might expect there to be records for cultivated plants in parks and gardens, because they were planted by people, and people can keep records.  But there is also extensive and intensive information available on many of the plants that grew without being planted by people, and for the animals that walked and flew among those plants.  Philadelphia’s rich history of natural history is unequalled for supplying this kind of information, and for keeping these records. [Note: There is also a record of a Herring Gull of which “Mr. Wm. Morris Whitaker also secured a specimen October, 1893, on a mill dam at Cedar Grove, Philadelphia, five miles from the Delaware.” from Witmer Stone’s “The Birds of Eastern Pennsylvania and New Jersey” (1894)]

And we can use those records, if we know about them, to learn about what was here before.  Or, if we don’t know about them, we can talk to those that do.  In 1910, Henry S. Borneman read a paper before the Historical Society of Frankford about the birds that were in the area, including Cedar Grove, in the late 19th and earliest 20th centuries.  Over a hundred years later, in 2012, Susan Couvreur and Diane Sadler, of the Historical Society of Frankford today, drew my attention to that work, with its richly detailed description of the bird life of Frankford, and also its discussions of the plants and habitats of the time.

There are also plants from Philadelphia that were, in many years past, collected, pressed, dried, and mounted on paper sheets, that are now deposited at the Department of Botany of the Academy of Natural Sciences of Philadelphia, and these plants that were collected decades ago provide evidence of what is no longer there.  There’s also a list of historic collections of plants from Philadelphia, that was extracted from the Plants of Pennsylvania database maintained by the Morris Arboretum, that was kindly provided to me by Ann Rhoads and Tim Block (botanists at the Arboretum).  This list provides an effective guide to the many collections from Cedar Grove that have been made in the past.

There were collectors in years gone by that allowed me to develop this wonderfully rich description of a site that has changed so much.  Walter Benner collecting sheep laurel (Kalmia angustifolia) on the 8th of July in 1926, in a moist thicket of Cedar Grove.  Samson McDowell, Jr collecting blueberry (Vaccinium corymbosum) in the moist woods there, on the 19th of May 1926.  These collections are now part of the Academy’s collections, and nearly 90 years later, their work allowed me to see first hand the plants that were there when they wandered through those open areas of Cedar Grove.

There are also maps, such as the 1895 and 1910 Bromley Atlases, from the Athenaeum of Philadelphia (available on, that show just how open the area was, how unbuilt it was a hundred years ago, and where the train line that cut through Cedar Grove went.

Taking these records, and applying some additional knowledge of ecology, we can describe Cedar Grove nearly as thoroughly as if we had walked through it ourselves – and a surprisingly detailed picture of this place in the early 20th century can be cobbled together.  Its open marshy areas and its forests, both of them rich with flowers and birds, the train line running through it, trees dotting the flats.  An evocative illustration can be drawn of a landscape that is no longer there.  And perhaps an evocative illustration can also be drawn of a landscape that is yet to be.