Cross-dressing birds on SFU campus
Each ruff is unique in color and plumage.
Dr. David Lank collects eggs in the aviary at SFU's Burnaby campus.
Dr. David Lank is a University Research Associate and Adjunct Professor in the department of Biological Sciences at SFU. He has been studying and breeding an eccentric sandpiper, the Ruffs, Philomachus pugnax, for 30 years. The name ruff is derived from the elaborate breeding plumage that many of the males exhibit, which resembles the exaggerated collars of the 16th and 17th centuries. These collars are like neckties, with each male having a different pattern, a unique characteristic among birds, and rare among all animals.
The ruff is a migratory shorebird that breeds in the low tundra marshes of Russia and northern Europe and winters in Africa, southern Asia and Australia. Lank studied the birds for six years in the wild before starting a breeding flock in 1985 with 40 eggs he imported from Finland. Finn Air provided special power to keep his incubator going for the transatlantic flight, and a few weeks later, Lank became the proud owner of 36 baby ruffs. Lank currently houses about 300 ruffs in an outdoor aviary on SFU’s Burnaby campus and breeds an additional 60 more ruffs every year, making SFU home to the largest ruff aviary on the planet.
What inspired Lank to devote his career to understanding these birds? Their unique and complex sex lives.
In many bird species, males help care for young, but in other species females provide all of the care, and males attempt to mate with as many females as possible. Ruffs fall into this latter group, and males in such species often have elaborate male plumages, courtship displays, and larger male size in hopes of attracting females. But ruffs have taken this type of process one step further than any other species of bird.
Three kinds of males exist in this species, each with its own approach to courtship and mating and with distinct physical characteristics. Most males (about 84%) are dark-plumaged “territorials”, which sport impressive plumages and exhibit exaggerated courtship behavior such as bowing and showy plumage displays. Then there are the whiter-plumaged, slightly smaller “satellite” males (about 15%). Although satellites compete with territorials to mate with females, each needs the other and they form an uneasy alliance. Since females prefer to breed when males are together, it is advantageous for territorial ruffs to have associates, even if females mate with the associate instead.
Finally, about 1% of males are “female mimics”, which lack elaborate male breeding plumage and do not exhibit conventional male displays. Mimics are smaller than males and slightly larger than female ruffs, but have testes 2.5 times the volume of other males. They have sex with both males and females and spend more time with the female population during the summer and the male population in the winter. Since they don’t exhibit masculine behaviors and they look more like the female, they don’t risk being chased away by territorial males. Mimics get their share of matings by rushing in to ‘sneak’ matings when females crouch on courts (a female mating signal), sometimes resulting in a piling up of males on top of females.
As to the evolutionary purpose of the mimics - that’s one mystery that keeps Lank fascinated.
The ruff is the only bird with three genetic types of males. Lank’s studies have proven that, contrary to most complex characteristics in most species, the differences in behavior and morphology among male ruffs are strictly governed by their genes and not by environmental factors. They lack developmental plasticity, which means that they do not change their mating behavior with social circumstances, or learn from experience.
What is the genome behind this and what is the ecological context that favored the evolution of such a system? Lank, in conjunction with colleagues at the University of Sheffield is sequencing the genome of the ruff to answer these questions. While this work progresses, Lank continues to breed and study them “because they are the most interesting bird in the world!”’