The greater sage-grouse (Centrocercus urophasianus) is a large ground-dwelling bird native to the sagebrush steppes of western North America. They are famous for their elaborate mating rituals that take place each spring on breeding grounds known as leks.
When does the greater sage-grouse mating season occur?
The mating season for greater sage-grouse begins in late February and runs through May. The peak of breeding activity typically occurs between mid-March and early April. This coincides with the early spring months when sagebrush leaves begin to grow and provide cover on the leks.
Where do greater sage-grouse perform their mating rituals?
Greater sage-grouse conduct their breeding displays on leks, which are open areas surrounded by sagebrush. Leks can vary in size but are typically between 0.4-4 hectares. The males return to the same lek site each year, displaying site fidelity. Dominant males occupy central positions on the lek while younger males remain on the periphery.
What do leks look like?
Leks are generally situated in open bowls or ridges with excellent visibility to allow males to keep watch for predators. The bare ground provides acoustically suitable habitat for the males’ vocal sac displays. Leks are typically surrounded by adequate sagebrush cover where females nest and find protection.
When do greater sage-grouse males arrive at the leks?
Male greater sage-grouse start arriving at the lek sites in late February and early March before the females. The males establish territory positions and begin competing with each other for dominance in preparation for the females’ arrival. The males will continue displaying on the lek for up to 3 months until breeding is done.
What displays do male greater sage-grouse perform?
Male greater sage-grouse perform elaborate strutting displays and vocalizations to attract females and intimidate competing males. Their main displays include:
- Strutting – Males puff out their chests, fan their tails, and rapidly stomp their feet to produce popping sounds.
- Vocal sac displays – Males vocalize with popping and whistling sounds, inflating the orange air sacs on their necks.
- Ritualized fighting – Males may spar with each other, jumping and kicking to establish dominance.
When do females start visiting the lek?
Female greater sage-grouse arrive at the lek later than the males, typically starting in early to mid April. They attend the lek during the early morning and late evening hours, moving under the cover of darkness to avoid predators. The females observe and select males based on their strutting displays.
How do females choose their mate?
Females do not mate randomly but exhibit choice when selecting a male. They prefer dominant males situated in the center of the lek who perform vigorous strutting displays. These males demonstrate good genes and fitness to possible mates. Females may also return to the lek on multiple mornings to compare males before copulating with a chosen mate.
How does mating occur?
Once a female has selected her preferred male, she will crouch down low and solicit mating by lowering her tail and raising her wings away from her back. The male will mount her for only a few seconds to copulate. No pair bond is formed and the male will continue his displays to seek additional mates.
When does mating activity peak?
Breeding activity reaches its peak between one hour before and after sunrise when the females visit the lek. This corresponds to the males’ most intensive displaying during the dawn hours. Upwards of 20 copulations may occur each morning at the peak of the season.
How many females will each male mate with?
Dominant male greater sage-grouse may successfully mate with 75-90% of the females that visit the lek. Older males with established territories at the lek center can breed with 15-25 hens. Younger peripheral males may not mate at all during their first year on a lek.
Do females nest near the lek?
After mating, the female leaves the lek and nests within a 2-3 mile radius in suitable sagebrush habitat with succulent forbs. Nest sites are typically under sagebrush cover or sometimes in the open near sagebrush. The female does not get any parental care from the male.
How many eggs does a female sage-grouse lay?
Clutch size ranges from 6-9 eggs, with 7-8 being typical. The female incubates the eggs for 25-28 days before they hatch. Eggs hatch synchronously in late May or early June. The chicks are precocial and can leave the nest shortly after hatching.
Summary of the greater sage-grouse mating ritual
In summary, the elaborate mating ritual of greater sage-grouse proceeds as follows each spring:
- Males arrive first at the lek and establish territories, competing for dominance
- Females visit the lek and observe male displays before choosing mate
- Dominant males may mate with majority of visiting females
- Mating peaks in early morning and lasts just seconds
- Females nest off-lek and raise chicks without male help
This unique breeding behavior ensures that the fittest males mate with the most females each season. Conservation of lek habitat is critical to preserving viable greater sage-grouse populations.
Threats facing greater sage-grouse populations
Greater sage-grouse populations have declined significantly over the past century due to habitat loss and degradation. Some major threats include:
- Sagebrush eradication to make way for agriculture
- Overgrazing by livestock
- Oil and gas drilling that fragments habitat
- Urbanization
- Invasive plant species encroachment
Lekking habitats are particularly sensitive to disturbance. Noise, tall structures, and human activity near leks can cause abandonment and impact mating success. Conservation efforts that protect intact sagebrush ecosystems are crucial for the future survival of sage-grouse.
Greater Sage-Grouse Conservation Status
Due to declining populations, greater sage-grouse are considered a species of conservation concern:
- They are classified as Near Threatened on the IUCN Red List
- Some distinct populations are Federally listed as Threatened or Endangered
- Sage-grouse are considered an umbrella species – protecting sagebrush habitat benefits 350+ animal species
Collaborative conservation initiatives across western states have sought to protect key leks and establish protected habitat zones. Continued long-term monitoring is needed to ensure the viability of remaining sage-grouse populations and the unique mating rituals they display each spring.
Fascinating Facts about Greater Sage-Grouse
- Males have yellow eye combs and two yellow sacs that inflate when displaying
- Their scientific name “urophasianus” means “tail-carrier” in Latin
- Long pointed tails aid in courtship displays and can reach 10 inches
- Their dark mottled plumage provides camouflage in sagebrush
- Weigh between 4-7 lbs with females slightly smaller than males
- Leks have existed in the same places for over 100 years
- Males eat sagebrush leaves prior to lekking to aid digestion
- Male displays can be heard up to a mile away on the lek
- Oldest known greater sage-grouse was over 9 years old
Key References
Here are some key scientific references about greater sage-grouse mating and lek behavior:
- Gibson, R.M. 1996. A re-evaluation of hotspot settlement in lekking sage grouse. Animal Behaviour 52(5): 993-1005.
- Gibson, R.M., J.W. Bradbury, and S.L. Vehrencamp. 1991. Mate choice in lekking sage grouse revisited: the roles of vocal display, female site fidelity, and copying. Behavioral Ecology 2(2): 165–180.
- Young, J.R., C.E. Braun, S.J. Oyler-McCance, J.W. Hupp, and T.W. Quinn. 2000. A new species of sage-grouse (Phasianidae: Centrocercus) from southwestern Colorado. Wilson Bulletin 112: 445–453.
- Schroeder, M.A., J.R. Young and C.E. Braun. 1999. Sage grouse (Centrocercus urophasianus). In: Poole, A. and Gill, F. (Editors). The Birds of North America, No. 425. Philadelphia, Pennsylvania: The Birds of North America.
Conclusion
The intricate mating rituals of greater sage-grouse provide a fascinating window into the lives and reproductive behaviors of these iconic birds. Each spring, flamboyant males strut, pop, and puff themselves up to win the attention of discriminating females on traditional lekking grounds. Successful mating is critical for greater sage-grouse to produce the next generation of chicks. Protecting the intricate web of sagebrush ecosystems these birds depend on is key to ensuring the future survival of their beloved springtime dances.