WHITE-TAILED DEER, BROWSING PREFERENCES

 MIDSUMMER BROWSING PREFERENCES OF A SUBURBAN LI, NEW YORK, WHITE-TAILED DEER HERD 

The White tailed Deer (Odocoileus virginianus) is a medium sized antlered ungulate native to most of North America and Canada, Central America, and the northern third of South America with isolated populations in parts of Central America.  There are an estimated 30 million deer in North America (See wikipedia) which in suitable habitats may weigh from 170 lbs for a buck (male) to 120 lbs for a doe.  In farming country or forested areas White Tailed Deer have a natural home range of about one square mile.  The species feeds mostly as a browser, feeding on the leaves and tender twigs of trees and brush, using their lower incisor teeth to tear off plant food. TheY have no upper incisors. They also eat grass and other low growing non-woody species as well as domestic crops such as corn and vegetable crops. Fruit and nuts are eagerly consumed when available as well.  They drink water when it is available, but can get most of their water from the food plants they consume as well as water produced by the digestion process.  Deer are ruminants that eat plant foods which, after maceration by molars, enters their stomach where fermentation  takes place in part of their four part stomach. They then regurgitate that food to chew it again for further digestion aided by microbial action. 

The most abundant and nutritious food sources for deer are found—not in the interior of shady forests as some might suspect—but on the margins between forest and open farm field, meadow, or roadsides. These often sunny, boundary zones or “edge habitat” produce the most and the greatest variety of plant food for deer. 

Suburban areas provide adequate habitat for deer since these partly urbanized areas are characterized by the natural spaces being  divided up by roads and housing and commercial areas which thus provide abundant and desirable “edge” habitat for deer. The suburban deer has few or no natural predators, and most often, no human hunters. This habitat also has well nourished, well watered plant foods in the form of grass lawns, foundation and decorative plantings, home gardens and well tended fruit and shade trees.

The deer population in Suffolk County, New York is estimated to be between 25,000 to 36,000 head as of 2014 (NYSC DEC Aug 4, 2014). With larger deer herds in suburban areas deer food preferences must have an impact on what plants may survive and prosper in parks, natural preserves, waste places.  plants wild are more likely to be impacted by deer browsing. Heavy browsing can alter population dynamics and intensify exacerbate invasive plant dominance or spread. 

But what do deer prefer in mid summer when heat may affect need for water, and when deer browse seems to be plentiful, at least to human observers?  What plant species are deer browsing on and what do they seem to prefer at the height of seasonal plant growth.  It is obvious that deer do seem to have specific preferences, which tends to limit their browsing locations and movements. The following brief observations may be of interest. 

Deer browsing preferences were observed in mid-summer 2024 along a rail road right-of way on Long Island Brookhaven Township, Suffolk County NY. This visual survey was conducted on July 18, 2024 along both sides of a one mile route of a bike-walk-jogging path, a former east-west Long Island rail road right of way, locally known as the Rail Path in Brookhaven Township between Rt 25A and Miller Place Road. The four meter wide asphalt path is bordered by a swath of recently cut mixed grasses and forbs which is in some areas confluent with patches of woodland of varying acreages. These provide adequate refuge or cover for deer. While the path itself is a continuous zone of edge habitat where they feed.  Parts of this zone are occupied by electric utility poles and pylons. Parts are bordered by housing development and others as noted above by forested areas. Whitetail deer are plentiful along this stretch of the “Rail Path”. 

Observations and records were made of the species of brush, vines and trees which showed obvious signs of recent deer browsing, branches and twigs devoid of leaves, with only petiole remaining, tooth marks, chewed twigs, branches bearing remnant leaves and chewed off tender terminals.

SPECIES OBSERVED BROWSED ALONG RAIL PATH..BETWEEN NY RT 25A AND MILLER PLACE ROAD, JULY 18, 2024.

Fox Grape(Vitis labrusca) especially young leaves and tendrils. (Most commonly browsed)

Multiflora Rose (Rosa multiflora) young leaves and tender branches.(Frequent)

Japanese Bittersweet (Celastrus orbiculatus)..tender leaves and tips of vines. (Frequent) 

Staghorn Sumac (Rhus typhina) both young leaves and especially the red fruit bodies (drupes0 of the terminal panicle were eaten off while the greEN panicle (infructescence) itself was left relatively undisturbed 

Field Bindweed ( Convolvulus arvensis) vine tendrils, flowers and leaves. (Frequent)

Catalpa  (Catalpa bignonioides) Leaves tender twigs browsed.(Few)

Flowering Pear (Pyrus sp) terminal leaves and twigs browsed.(Few) 

INCIDENTAL OBSERVATIONS (not recorded at this date). 

Other species browsed: 

Poison Ivy (Toxicodendron radicans) A telephone pole with heavy growth of the poison ivy climbing vine was observed to have been browsed by deer. Typical height, and vegetation effects of deer browsing were observed. This during early spring of 2024.

Chicken Mushroom (Laetiporus sulphureus) observed a large shelf fungi on a lightning struck Black Oak tree about three feet above ground. The fungi had clearly been chewed by ungulate. On a later observation two days later most of the remaining portion had been chewed off and removed. This observation in the early spring of 2024 within the one mile path zone of this report 

Virginia Creeper (Parthenocisssus quinquefolia) Ocasionally browsed in this study area. But most observations of browsing were associated with presence of C.orbiculatus. Perhaps this species simply eaten by deer accidentally as they seek favored Bittersweet. 

 

VERY COMMON SPECIES NOT BROWSED AT TIME OF THIS OBSERVATION

Though very common among other forbs, brush and minor tree species and available at heights deer could reach all along one mile path, no evidence of browsing was observed on these common species.

Eastern Red Cedar (Juniperus virginiana) This species is heavily browsed in winter but no observations of browsing were observed at the time if these observations. Most trees had abundant light green new terminal branch growth but none showed evidence of browsing.

Russian Olive (Elaeagnus angustifolia)

Black Locust (Robinia pseudoacacia)

Black Cherry(Prunus serotina)

Norway maple (Acer platanoides) 

Paulownia tree (Paulownia tometosa)

Poke weed (Phytolacca americana)

Red Raspberry (Rubus idaeus)

Crown Vetch (Secuigera varia)

CONCLUSION: Wherever Japanese Bittersweet (C.orbiculatus) or Fox Grape (V. lambrusca) were available to be browsed  by deer, i.e.  within 1.5-2 meters above ground,  in the described study area these species were heavily browsed.  One may use such browsing as high probability of White tailed deer in significant populations levels. 

Addendum

By July 30, 2024, much of the preferred browse noted above along the Rail Path corridor had been consumed by deer. Late in the month this author observed the preferred species noted above had been heavily browsed and were in the process of regrowing leaves on branches that had been denuded or browsed clean. These new growths appeared unaltered by browsing deer. 

On these last days of July perhaps being hungry, deer were observed browsing actively on foundation plantings located on adjacent  property. The browsed foundation plant were identified as  commonly planted, Yew (Taxus sp?) Probably  T. Canadensis)  On July 28, author  observed young fork horn buck and yearling  doe grazing in high grass which borders the Rail Path.  Apparently the preferred species described above were not enough to satisfy their hunger and late in July deer here began grazing. 

By mid to late September, acorns were falling from oaks, and these were eagerly eaten by deer. A pair of yearlings were observed regularly gleaning acorns fallen to the roadbed. These two favored a busy corner along North Country. Road where fallen acorns were often crushed by vehicles truning into a side road. The crushed acorns seem to be preferred…or perhaps  they were simply more easily seen and exploited on the hard asphalt surface.  Sadly the attraction to these  crushed acorns brought them into  contact with a busy road. 

In addition, around this time fallen fruit, apples, and pears fallen onto lawns and even close to homes were also eagerly eaten.