Bird Mating Ritual

 The groundhog may not have seen his shadow this year, but that does not mean the mating season will be delayed for Nevada’s birds. In fact, some birds have already begun to mate.  The sandhill crane, for example, began mating back in December and, in non-migratory populations, it will continue to mate until April.  Sandhill cranes can be observed in the Ruby Marshes and in Lamoille Valley.

As a juvenile, this majestic wading bird is not much of a spectacle, but as it reaches adulthood, hormones will trigger changes in appearance. Both males and females of the species will molt their ochre-colored baby plumage (feathers) and develop mostly gray feathers, white cheeks, and red crowns.

To attract a mate, the male and the female will engage in a unique courtship ritual known as unison calling. During unison calling, they will participate in a dance display and a synchronized duet. The sandhill crane will mate for life and continue this ritual with their partner every year.

Another early breeder, renowned for its unique dancing display is the greater sage grouse. Sage grouse are the most common grouse in Nevada, and can be found in 15 of the 17 Nevada counties.  Every year, this sagebrush-obligate galliforme (ground feeding bird) gathers in groups known as leks where males (cocks) will compete with each other for females (hens). Unlike the sandhill crane, though, the greater sage grouse will not mate for life, but seek out a new partner each year. In addition, hens will typically mate with only three out of the eight available cocks per lek, leading some cocks to form harems.

In cocks, hormones will trigger their spiky tail feathers to fan-out and their giant yellow air sacs to become more prominent. To attract a hen, the cock will gobble up the air, creating a popping noise as it flashes its air sacs.

Hormones will also trigger physical changes in sagebrush-obligate songbirds like the Brewer’s sparrow and sage thrasher, specifically by enlarging their larynxes. This enables them to project their calls over long distances so that they can defend large amounts of territory and attract mates. The sage thrasher will mate with a single partner each year and the Brewer’s sparrow will mate with multiple, forming a harem. Though not as ostentatious (noticeable) as the greater sage grouse, these charming little birds make up for their drab plumage with their melodic songs.

Unfortunately, the songs and dances of these iconic birds have been disappearing in the wild due to the loss of their habitat. As you get outside to do some bird watching, enjoy the sounds of nature that come from our feathered friends.  Remember to be consciousness and respectful of their space, keep your distance while witnessing the awesome that nature has to offer.