For example, in the words of the National Deer Association:
“The best option is to give deer more of the winter foods they are already adapted to eating: winter browse. This includes buds and twigs of woody plants. Introducing new foods in the middle of winter, especially in high quantities all of a sudden, can actually be more harmful to deer than not feeding them at all …” because deer can’t gain nutrition from foods that their gut micro-organisms are not adapted to digesting. Thus, in late winter, "deer carcasses can begin to pile up."
There are at least two things wrong with this perspective. The first is that it may be counterproductive to give deer extra food to keep them alive in winter where deer are overpopulated, diseased, and badly degrading the ecosystem. The second is that the over-dependence on twigs may be largely a reflection of the ecological degradation in our woods and savannas.
To put that second point differently, ecosystem managers have allowed habitats to become so shady that most herbaceous (non-woody) plants have died - and the few palatable ones that remain get drastically reduced or eliminated by the deer..
At Somme, we’ve long noticed that deer in late winter (when favorite foods like acorns and deer-level twigs have already been eaten) spend a lot of time “grazing” green sedges and dried wildflower leaves. Check out the video below:
The closest deer is eating prairie doc leaves in our back yard. The three deer in the background are eating dried aster and goldenrod leaves.
Across the street in Somme Prairie and Somme Prairie Grove Nature Preserves, the deer this time of year spend lots of time grazing in areas that we know well as having few woody plants. When we study these deer with binoculars, they’re clearly eating green sedges and dried wildflower leaves. There are huge amount of those foods there.
Are there any useful lessons here?
Perhaps these?
1. It’s interesting to see another example of how degraded ecosystems lead to false conclusions.
2. Many deer at many sites leave the preserves in winter to eat prized shrubs in people’s landscaping across the streets. In a way, this is a form of population control, since many of those deer sooner or later get hit by cars and die. But that’s a very poor solution, for the deer, for the homeowners, and for the folks driving the cars.
3. As many have pointed out, buckthorn berries are edible and nutritious, but buckthorn bark and buds are poisonous (cathartic). So stands of buckthorn that are too high for deer to reach berries – or so low that they’re all branches and no fruit – are the very poor habitats for deer (and most wildlife).
4. All this is another argument for restoring full plant diversity to conservation lands.
Across the street in Somme Prairie and Somme Prairie Grove Nature Preserves, the deer this time of year spend lots of time grazing in areas that we know well as having few woody plants. When we study these deer with binoculars, they’re clearly eating green sedges and dried wildflower leaves. There are huge amount of those foods there.
Are there any useful lessons here?
Perhaps these?
1. It’s interesting to see another example of how degraded ecosystems lead to false conclusions.
2. Many deer at many sites leave the preserves in winter to eat prized shrubs in people’s landscaping across the streets. In a way, this is a form of population control, since many of those deer sooner or later get hit by cars and die. But that’s a very poor solution, for the deer, for the homeowners, and for the folks driving the cars.
3. As many have pointed out, buckthorn berries are edible and nutritious, but buckthorn bark and buds are poisonous (cathartic). So stands of buckthorn that are too high for deer to reach berries – or so low that they’re all branches and no fruit – are the very poor habitats for deer (and most wildlife).
4. All this is another argument for restoring full plant diversity to conservation lands.
Just found this entry when search for a remnant prairie reference for an Eagle Scout project. Glad to see you are observing deer and reporting the observations - interdisciplinary ecological studies will be important to better inform us of the various aspects in our work. I didn't know dried leaves were a food source for deer - makes me think that fall burning would remove that food - and send the deer elsewhere. Many hypothetical combinations of stewardshiip actions on deer habitat, but generally I have been promoting the idea of making our nature preserves and other natural area so abundantly diverse and resilient as to better withstand any grazing - in this way ecosystem function can return and the largest mammal remaining naturally in the region can somehow fit in to the "wildland-urban interface."
ReplyDeleteIn northwest Grant County, Wisconsin deer have been captured on camera eating dead prairie in winter. However, with the deer population being so high in the area it may be because there isn’t any browse left and they’re eating what’s available.
ReplyDeleteAn interesting study on the diversity of plants consumed by deer over the course of the year is WHITE-TAILED DEER FOOD
ReplyDeleteHABITS AND PREFERENCES
IN THE CROSS TIMBERS AND
PRAIRIES REGION OF TEXAS.
It isnt a local study but I imagine deer have an equally diverse diet over their range as this area of Texas.