Northern Prairie Wildlife Research Center
|The annual turnover rate in a pheasant population is about 70 percent. Thus the nesting season, when new birds hatch, is a critical time of year for the ring-necked pheasant in North Dakota|
Usually beginning in late March, and peaking in May, roosters claim territories. Within these areas, which may range in size from a few acres to a half section or more, the roosters strut and crow, tolerating no intrusion by other males. A rooster's raucous crowing, followed by a rapid beating of wings, proclaims that this is his territory; his aggressive behavior apparently demonstrates to prospective mates that his is desirable genetic material, and that his offspring are likely to be hardy.
|A territorial ring-neck proclaiming his domain.|
The second and most dramatic phase of courtship occurs after the hen is attracted to a rooster's territory. He approaches the hen, tilts his body toward her, spreads his tail feathers, and extends one wing downward. His head is held low with ear tufts erect and neck feathers flared. The lores (or wattles) on the sides of his head turn a vivid shade of red and swell until they nearly touch on top of the head. His yellow eyes appear vacant, and he seems to be completely ruled by the biological instinct to reproduce.
Early in the season, hens show little if any interest in the rooster's displays. They may watch briefly, then continue feeding. As the nesting season approaches, hens become more attentive, and finally they select roosters with which they will breed. Pheasants are polygamous, and a rooster will gather as many hens as possible into a "harem." In North Dakota the average harem is three or four hens, but it is not unusual to see as many as eight.
|As the nesting season approaches hens become attentive
and select roosters with which they will breed.
The gender ratio in the spring breeding population usually averages about 2 1/2 hens per rooster. Since harems average three or four hens per rooster, there are always roosters which do not mate. "Bachelor" birds tend to be a disturbing influence in the breeding population, roaming about as they try to gather their own harems, picking fights and assaulting hens.
All of these bachelor roosters and even many of those which did acquire mates, are surplus to the reproductive needs of the species. A spring sex ratio of six to 10 hens per rooster would be sufficient to ensure species reproductive success. After fertilization takes place, courtship ends. The hen chooses a nest site, lays and incubates the eggs, and broods the chicks with no help from the male, whose reproductive role ends with mating.
Early in the nesting season, hens may seem rather careless about egg laying. Eggs may be dropped at random and left unconcealed.
Later, a hen may initiate a nest, lay a few eggs in it, and then abandon it. Frequently, several hens lay eggs in a single nest, termed a "dump nest" by biologists. It is not uncommon for a dump nest to contain 20 to 30 eggs. As spring progresses, random egg laying ceases.
Pheasants are ground nesters, whose nests consist of small depressions lined with grass, leaves and other plant material. Down, feathers and additional vegetation are added as egg laying and incubation progresses.
Nests are established in a variety of vegetation types, and studies suggest that local availability dictates the hen's choice. In some states, pheasants rely heavily upon small grains for nesting. In North Dakota most of our small grains are planted too late in spring to be able to provide quality nesting cover. The small grain harvest normally begins during July, well after the peak of the pheasant hatch. Hens that lose early nests and choose small grain fields as renesting sites may also be successful, even if fields are harvested prior to hatching, since stubble is normally left high enough to provide sufficient cover and many hens return to complete incubation after harvest.
Predation of nests is lower in small grain than in any other cover type because nests are spread over a large area and nest predators, such as striped skunks, are more likely to hunt in strip cover such as fencerows and roadsides.
Alfalfa is attractive nesting cover in North Dakota. However, a high percentage of nests in alfalfa are destroyed by mowing, which occurs just prior to the peak of hatch. Often these nests become death traps for incubating hens. Chicks that do hatch before mowing are usually too young to escape the swather and hens are often killed with their broods as they try to protect them.
A nesting hen lays eggs at a rate of about one per day. She remains at the nest only to deposit eggs, which may number from one to 20 when the clutch is completed; the average in North Dakota is 11 eggs.
|A nesting hen lays eggs at a rate of about one per
day until her clutch is completed. She may lay up
to 20 eggs, but frequently lays less. The average in
North Dakota is 11 eggs.
When the clutch is complete, incubation begins. Just prior to egg laying, hens shed breast feathers, exposing a bare patch of skin. This "brood patch" is well supplied with surface blood vessels, and keeps the eggs at the proper temperature for hatching. During egg laying, the hen seems only a casual visitor to the nest, staying just long enough to deposit each egg. During incubation, however, she leaves the nest only for a brief period each day.
Pheasant eggs require approximately 23 days of incubation. During this period, the hen turns the eggs frequently. Although eggs are laid individually over a two-week period, incubation of all eggs begins at the same time and all hatch within a few hours of each other.
When development is complete, the chick uses its egg tooth, a projection on top of the beak, to cut the cap off the large end of the egg. Although pheasant chicks hatch from May through August, studies indicate that from 30 to 60 percent of all chicks hatch during the last two weeks of June. The chicks emerge as wet balls of fluff supported on spindly legs. Pheasant chicks are precocious, capable of leaving the nest soon after hatching, and the hen will lead the brood away from the nest as soon as they are dry.
The majority of nesting failures can be attributed to three factors - farming operations, predation, and nest abandonment. All have varying effects from area to area and from year to year, but generally when abandonment rates rise, nest failures from predation and farming operations fall, and vice versa. Generally speaking, high nesting success occurs in years when spring weather is warm and dry.
Habitat, as a factor affecting nest success, is a much discussed topic, but its true importance - providing secure nesting cover - is seldom fully recognized. Moreover, habitat quality is the one factor in nesting success over which man can exert a degree of control, and thus modify the impact of weather, predation, farming losses and abandonment.
Fertility is not a problem in North Dakota's pheasant population. Examination of hundreds of eggs indicates that fertility consistently averages over 90 percent.
North Dakota pheasants are persistent nesters. Hens do everything in their power to nest successfully, and will make multiple nesting attempts. Pheasants are not noted for their longevity; average life span of a North Dakota pheasant is less than one year, and few birds live to see two successive hunting seasons. The annual turnover rate in the population approaches 70 percent.
In any year's population, nearly 80 percent of the birds are young-of-the-year. Thus the nesting season, when these replacement birds are produced, is the most important time of the year for North Dakota's pheasants.