Habitat & Conservation  |  05/10/2016

Roadsides: Ecological Traps or Opportunities to Provide Habitat?

Increasing acres of row crops in the Midwest and elsewhere has eliminated quality nesting habitat for many grassland bird species, including the ring-necked pheasant. Without large tracts of grassland habitat for nesting, roadsides can offer an attractive alternative to nesting birds.
In fact, about 25 percent of Minnesota’s hen pheasants may use roadsides for nesting. An even greater percentage of pheasants use roadsides for brood-rearing because hens and their chicks prefer to move to warm, dry areas like gravel roads in late summer when the grass is heavy with dew.
A roadside, however, can become what is termed an “ecological trap” – a habitat type that looks suitable for reproduction, but is in reality unsuitable. Ecological traps lead to decreased reproductive output and survival. One common concern is that roadsides can be used as travel corridors for predators, offering a smorgasbord of nests to feed on along the way.
But another, perhaps more devastating concern is human disturbance to roadsides during the nesting and brood-rearing period. These disturbances can include turning farm machinery around, riding motorcycles or all-terrain vehicles (ATVs) and mowing or haying. In some parts of the pheasant range, including Minnesota, roadsides are frequently mowed or hayed at least once (but sometimes multiple times) during the pheasant breeding season.

Roadside Habitat for Nesting

The timing of the nesting season varies across states and regions and is influenced by a variety of factors, including weather and habitat conditions in the spring. If everything goes according to plan, many nests will hatch within a few weeks of each other. But, inevitably, some hens fail with their first nesting attempts and need to re-nest. No matter the case, a hen needs at least six weeks to lay all her eggs and incubate them.
Hens are VERY attentive while incubating a clutch of eggs. More often than not, a hen will rely on her camouflage to remain undetected during this vulnerable time. This means that a hen will often opt to stay on her nest rather than fly if a disturbance comes along. Given their very cryptic coloration and well-hidden nests, this is often a good strategy. Unless the disturbance is a mower!
Many hens hold tight when a mower comes along, and unfortunately the outcome is often immediately fatal. In some cases, a lucky hen may escape, but whether she lives to re-nest another day depends on the extent of her injuries.

Roadside Habitat for Brood-Rearing

Roadsides are heavily used during the brood-rearing period, too, because they offer the best of both worlds: a dry, sunny gravel road to warm up along and some thicker vegetation to run and hide in should a predator or other threat come along. Also, some pheasants use roadsides as travel corridors to get their chicks from one habitat patch to another.
But just because a nest successfully hatches doesn’t mean that the hen and her chicks are now safe. Chicks are not capable of flying when they first hatch. By a few days of age, they are capable of making short hops and jumps. But it takes at least 7-12 days before they can fly even short distances. Even then, their flight muscles will quickly tire out if they’re repeatedly flushed, and they’ll soon choose to run rather than fly. Therefore, mowing and haying operations during the first few weeks of a chick’s life can also have fatal consequences.

Delay Mowing and Avoid Disturbance

So how can we make roadsides productive for breeding birds and avoid the ecological trap scenario? The easiest answer is to not disturb them in the first place. But for many agricultural regions, that’s not a realistic option. In these cases, there are some guidelines that wildlife managers can offer. First, delay roadside mowing whenever possible, with August 1 being a good target date recommended by Pheasants Forever. The longer any mowing or haying operations are delayed, the greater the chances a hen can successfully nest and raise her brood to an age where they can escape machinery. If visual safety along a roadside is a concern, then landowners can mow a narrow strip near their mailbox and along the road, which leaves the bulk of a roadside undisturbed.
Obey the laws on mowing and haying that are appropriate for the specific location of that roadside. Many people have trouble keeping various township and county laws straight, so contact your township or county board if you need help understanding these laws. Finally, avoid other activities that may disturb breeding birds. Ride ATVs when/where appropriate. And don’t use roadsides to turn vehicles or heavy farm machinery around.
Finally, consider enhancing the attractiveness of roadsides for pheasants, other nesting birds, pollinators and other insects (also known as chick/adult food) by encouraging the growth of flowering plants (also known as forbs). A high-diversity plant mix that includes grasses and forbs provides diversity in both vegetative structure and composition that is appealing to a wider variety of wildlife.
Story by Nicole Davros, Ph.D., is the Upland Game Project Leader for the Minnesota Department of Natural Resources.
Photo Credits: Minnesota Department of Natural Resources