White-Tailed Deer

Philadelphia is full of deer. Give them a large greenspace connected to other greenspaces (by a creek, railroad tracks, river shoreline), and they'll make themselves at home. 
 
If this surprises you, it's only because they're so good at avoiding us. Learn about their sign - the evidence of their activities - and you'll recognize it everywhere. 
 
Description
 
You're probably familiar with white-tailed deer as our default deer in the United States. If someone says "deer," this is usually what they're talking about. They appear in TV commercials, show up mounted on hunters' walls, and starred in Bambi. 
 
They have tan fur with a large white patch on the rump, revealed as a warning flag as they "hightail" it away from danger. Bucks (males) grow antlers in the fall to fight with rivals for the opportunity to mate with does (females). In the winter, once the breeding season is over, they shed the antlers. Females do not grow antlers. 
 
Fawns are born in May with the iconic white-spotted pattern on a reddish-brown background. This fades to the adult tan color as they grow. 
 
Bucks will grow to about 140 pounds and about 33 inches tall at the shoulder. Does are a little smaller. 
 
Habitat
 
Whitetails prefer a mix of forest and meadow or field, and both urban greenspaces and suburban neighborhoods offer plenty of that "edge" habitat. They might bed down for the day in heavy brush or dense woods and then wander out at dusk to feed in a meadow. 
 
Diet
 
Deer eat a wide variety of vegetation but prefer to browse leafy plants rather than graze grass like a cow would. In the winter, they'll eat leaf buds from bushes and low tree branches and add fruit and acorns to their diets when available. 
 
Behavior
 
White-tailed deer avoid humans and are mostly active when we are not. Although you can sometimes spot them feeding during the day, they generally come out at dusk and bed down shortly after sunrise. 
 
An alarmed whitetail will make a sharp snorting sound, warning others of danger, leading the group to bound off into the woods to hide. Thus what the human observer hears - often before they know there are deer nearby - is that snort followed by the crashing of deer running through the underbrush. 
 
In the fall the bucks rub off the thin layer of skin (velvet) that has covered their growing antlers, often on small trees and saplings. They then use their antlers to fight for the opportunity to mate with does. The fawns are born in May and stay hidden in vegetation as their mothers feed. 
 
Does will often leave their fawns hidden in grass or forest underbrush. These fawns respond to danger by staying still and relying on their pattern for camouflage. 
 
History of White-Tailed Deer with Humans
 
Deer, ahtuhw," served as a critical resource for the Lenape before European colonization: a source of meat as well as hides for clothing and materials for tools from bones, sinews, and antlers.
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Although deer are abundant today, this is thanks to a recent recovery. Deforestation combined with heavy hunting pressure made deer scarce by the early 1900s. Reintroduction efforts combined with regrowth of our forests and hunting regulation offered deer the perfect conditions to bounce back.
 
Suburban settings and urban parks offer deer their favorite habitat mix combined with near-freedom from predators such as wolves, mountain lions, and human hunters. The result is that deer populations can grow so dense that they have a negative impact on habitat for other species. Deer that intensively browse forest undergrowth prevent tree and shrub saplings from growing, eliminate native understory plants, and often encourage the growth of exotic, invasive plants they don't eat. 
 
Observing White-Tailed Deer
 
It can be difficult to see deer in the flesh, since they are active when we are not, and they are masters at avoiding us: 13,000 years of being hunted by humans has resulted in deer that keep a close eye on us and get out of our way before we even know they're there. 
 
Luckily deer leave plenty of signs for us to observe. Deer travel along well-worn paths through their habitat. If you see what looks like a narrow path through the woods, and that path seems to go right under branches that would smack a human in the face, you're probably looking at a deer trail. Following these trails can reveal deer droppings (like small piles of marbles, though they can clump together depending on deer diet) and other sign such as bedding areas and saplings with their bark scraped off by males rubbing their antlers in the fall. 
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Also look for deer footprints in mud or snow. Their cloven hooves (in two parts, split down the middle) are difficult to confuse with anything else. 
 
Living With White-Tailed Deer
 
Deer can be tough to live with. When their populations are high they will help themselves to plants in your garden, damage forest understories, and wander out into the street, where they often get hit by cars - usually lethal for the deer and dangerous for the humans too. 
 
Land managers use several tools to control deer impact. You can find several deer exclosures in our parks. These are sections of woods fenced off by tall fencing that deer can't cross, giving the forest inside a chance to recover. Land managers also control populations by bringing in contracted shooters to cull the population. 
 
More Resources
 
PA Game Commission White-Tailed Deer Website 
iNaturalist observations of white-tailed deer