The deer population of Lower Merion Township dropped 30 percent from 2008 to 2012, but according to a U.S. Department of Agriculture survey, it's still four times higher than recommended for the suburban area.

White-tailed deer have been problematic in the township for decades, causing car crashes, degrading forest land, and increasing the risk of Lyme disease.

The population density dropped from 58 deer per square mile in 2008 to 40.5 in 2012 - a conservative estimate, according to the USDA. Density is greatest on the northeast end of the township, around Gladwyne.

For suburban areas like Lower Merion, the recommended density is less than 10 deer per square mile.

In 2012, there were 65 deer-vehicle collisions. That's just slightly over the annual average, following a high of 124 in 1994.

The deer population has also degraded most of the township's dense forest areas, clearing space for invasive species like English ivy, Chinese privet, and bamboo to take root. Deer don't eat those plants, so in subsequent years they turn to landscaping for food, the USDA report says.

Lower Merion encourages sport hunting to control the deer population, but because it's a residential area, hunters are allowed to use only shotguns or bows, and only in certain areas, with homeowners' permission.

"Professional" hunters with the USDA's Wildlife Services have been more effective, culling roughly 100 deer a year in Lower Merion since 2009.

Some residents and animal-rights advocates object to culling. Alternatives like fertility control and relocation are not allowed in Pennsylvania.

Contact Jessica Parks at 610-313-8117, jparks@philly.com or follow on Twitter @JS_Parks.