The Ross’s goose (Chen rossii) and the blue goose (Chen caerulescens) are two closely related species of geese in North America. Both belong to the genus Chen, which also includes the smaller snow goose. Ross’s geese and blue geese look very similar but have some distinct differences in their anatomy and behavior. Understanding these differences can help bird watchers and hunters distinguish between the two species.
In the opening paragraphs, we will provide quick answers to key questions about Ross’s geese versus blue geese. Then the remainder of the article will go into more detail on comparing their appearance, distribution, migration, diet, mating and reproduction.
Quick Comparison
What does a Ross goose look like?
– Small, about the size of a mallard duck
– White overall plumage with black wingtips (“salt and pepper” look)
– Short, stubby bill that is black at the base fading to pink at the tip
What does a blue goose look like?
– Slightly larger than a Ross goose, similar in size to a snow goose
– White plumage with a distinct white “grinning patch” on the face
– Black legs and feet (Ross geese have pink legs and feet)
– Longer neck than a Ross goose
Where do they live?
– Ross geese: Central Arctic and mid-continent North America
– Blue geese: Coastal Arctic and Western Interior of North America
How far do they migrate?
– Ross geese: Migrate from Arctic coast to California and Mexico
– Blue geese: Migrate from Arctic coast to Gulf of Mexico
Appearance
Ross’s geese and blue geese appear very similar at first glance. Both have predominantly white plumage on the head, neck, back, and underside. However, careful observation reveals some key physical differences between the two species:
Size:
- Ross’s geese are the smaller of the two, measuring about 21–25 inches in length with a 38–42 inch wingspan. Their average weight is 3.0–3.5 lbs.
- Blue geese are slightly bigger at 26–34 inches long with a 48–54 inch wingspan. They weigh 4.4–6.6 lbs on average.
Coloration:
- The white plumage of Ross’s geese extends fully up the neck to the base of the head. They have black lines on the chin and throat.
- On blue geese, the white stops at the neck and creates a distinct white “grinning patch” from the base of the bill back towards the eyes.
Bill Morphology:
- Ross’s geese have a very short, stubby bill that is black at the base and pink at the tip.
- Blue geese have a longer, more uniform bill that is black to grey-blue in color.
Feet and Legs:
- Ross’s geese have pink legs and feet.
- Blue geese have black legs and feet.
Wing Patch:
- Both species have black wing tips (“salt and pepper” look). However, the black extends further up the back edge of the wing on blue geese compared to Ross’s geese.
So in summary, blue geese tend to be slightly larger with a different bill shape, facial markings, and coloration on the legs/feet and wings compared to Ross’s geese. Being able to recognize these subtle differences is key to telling the two species apart.
Distribution and Migration
Ross’s geese and blue geese have overlapping but distinct breeding and migration ranges:
Breeding Grounds:
- Ross’s geese nest in the central Arctic region, mainly around the Queen Maud Gulf. Some may nest further west into the high Arctic.
- Blue geese nest along the coastal low Arctic from Banks Island to Baffin Island. Some may intermix and hybridize with Ross’s geese in the central Arctic.
Wintering Areas:
- Most Ross’s geese migrate down the Central Flyway to winter along the Pacific Coast from California to Mexico.
- Blue geese primarily take the Mississippi and Central Flyways to winter along the Gulf Coast from Texas to Mexico.
Migration Stopovers:
- Ross’s geese stopover in massive numbers on prairie marshes, lakes and grain fields in the Great Plains along their central migratory route.
- Blue geese migrate through interior wetlands and farmlands, mixing with mid-continent snow goose flocks.
So in general, Ross’s geese follow a more direct north-south migratory path down the center of the continent, while blue geese spread out further east and west along more variable coastal and interior routes to their wintering grounds. However, there can be substantial overlap during migration and wintering periods.
Diet and Feeding
Ross’s geese and blue geese are both herbivores that feed predominately on plant material:
Summer Diet:
- In their Arctic breeding grounds, they eat sedges, grasses, moss, lichens and aquatic plants.
- They also graze on grains like wheatgrass, ryegrass and fescues when nesting near agricultural areas.
Winter Diet:
- On migration and wintering grounds, they feed heavily on waste grains in agricultural fields, especially rice, corn and wheat.
- They also continue to graze on native grasses, sedges, salt marsh plants and winter cereals.
Feeding Behaviors:
- Both species feed on land by grazing, picking, pecking and gleaning vegetation.
- They also upend and dabble in shallow water to reach submerged aquatic plants.
- Ross’s geese tend to be more aggressive competitors during feeding. Large dense flocks bully blue geese away from preferred food sources.
The diet of Ross’s and blue geese overlaps significantly in most regions. However, subtle differences in bill structure may allow blue geese to access some food items more efficiently, such as digging roots from mud. When competing for the same food resources, the larger blue geese are typically subordinate to the more aggressive Ross’s geese flocks.
Mating and Reproduction
Ross’s geese and blue geese have similar reproductive biology but some key differences in their mating behaviors:
Breeding Season:
- Both species breed in late May through early June during the short Arctic summer.
- The timing of nest initiation can vary slightly between the two, with blue geese starting 1-2 weeks earlier on average.
Pair Formation:
- Ross’s geese form lifelong pair bonds that re-unite each breeding season.
- Blue geese more commonly form new pair bonds each year after migrating back to breeding grounds.
Nest Sites:
- Ross’s geese nest in colonies on small Arctic islands and peninsulas, often in sloping hollows.
- Blue geese nest in solitary pairs or loose colonies near ponds, lakes and rivers on the tundra.
Clutch Size:
- Typical clutch size is 3-5 eggs for both species.
- Ross’s geese may lay slightly larger clutches on average.
Incubation:
- In both species, the female incubates the eggs while the male remains nearby to stand guard.
- Incubation period lasts 22-24 days.
Brood Care:
- Goslings hatch synchronously and are led by the parents to nearby water.
- Families may join together in large crèches, especially in Ross’s geese.
- The young fledge at 4-6 weeks and migrate with the adults thereafter.
The breeding strategies of Ross’s and blue geese are adapted to their particular nesting environments. Ross’s geese are colonial nesters, so mating for life ensures both parents cooperate to raise young. Blue geese nest more dispersed, allowing for annual pair formation. However, both species ultimately work together as mated pairs to incubate eggs and shepherd goslings to adulthood.
Population Status
Both Ross’s geese and blue geese have thriving, growing populations:
Ross’s Goose:
- Global population estimated at over 1 million birds.
- Numbers were less than 10,000 in the 1930s, but have boomed over the past 50 years.
- Population increased at rate of 7.9% per year from 1966-2015.
- Considered a species of Least Concern by the IUCN Red List due to increasing population trend.
Blue Goose:
- Global population estimated between 500,000 – 1 million.
- Also rebounded after early 20th century population lows.
- Though still increasing overall, growth rate has slowed to 1.1% per year.
- Considered a species of Least Concern by IUCN Red List due to large and stable population size.
The rising numbers of Ross’s and blue geese is attributed to several factors:
- Legal protection from hunting in early 20th century allowed populations to recover.
- Increased availability of cereal grain crops in migration and wintering areas provides abundant food.
- Northward expansion of breeding grounds provides more nesting habitat as Arctic warms.
- Reduced mortality from disease and predators.
High populations levels of both species have led to concerns about potential impacts on tundra vegetation and agricultural crop damage. Some more restrictive hunting regulations have been implemented in recent years to control numbers. Otherwise, Ross’s geese and blue geese remain common and widespread across North America.
Interactions with Humans
Abundant Ross’s goose and blue goose populations interact with humans in a variety of ways:
Hunting:
- Both species are legally hunted, with blue geese comprising the majority of the harvest.
- Over 1 million white geese (including snow geese) are harvested in the U.S. and Canada annually.
- Hunting is carefully regulated with daily bag limits and possession limits.
- Some “conservation order” hunts have allowed more liberal taking of blue geese to control populations.
Crop Damage:
- Large flocks can damage agricultural crops such as rice, corn, winter wheat, etc.
- Grazing in grain fields occurs during migration and wintering periods.
- Most damage complaints concern snow geese, but blue geese and some Ross’s geese may contribute.
- Farmers may get government permits to haze or take geese causing crop depredation.
Bird Strikes:
- Migrating or wintering flocks are hazardous to aircraft taking off and landing at airports.
- Collisions between geese and planes have caused damaging and sometimes fatal crashes.
- Population control and hazing techniques are used to reduce bird strike risks.
Tourism:
- Birders enjoy observing snow goose and blue goose staging and wintering grounds, like Squaw Creek National Wildlife Refuge.
- Watching the massive spring migration of white geese is a popular ecotourism activity.
- Some communities even hold festivals centered around arrival of the geese.
Overall, the thriving populations of Ross’s geese and blue geese provide recreational hunting opportunities and wildlife viewing enjoyment for many. But their abundant numbers also create some economic and safety conflicts with agricultural producers and aviation. Wildlife managers continue working to find a balance between goose conservation and controlling problematic impacts.
Conclusion
In summary, Ross’s geese and blue geese share similarities as close taxonomic relatives and tundra-breeding migratory geese. However, paying attention to differences in their size, plumage details, bill and foot morphology, distribution, behavior, and voices can help observers confidently distinguish between these two species. Blue geese tend to be somewhat larger and stockier with black feet, while Ross’s geese are smaller and daintier with pink feet. Ross’s geese breed in denser inland colonies, migrate in a narrow corridor down the Central Flyway, and form lifelong pair bonds. Blue geese nest along the Arctic coast in solitary pairs, spread out more widely on migration, and re-pair annually. Both species have made dramatic population recoveries in recent decades, which has led to complex management challenges involving hunting regulations, agricultural crop damage, and aviation hazards. Continued research and monitoring is needed to ensure healthy numbers of Ross’s geese and blue geese across North America while also minimizing conflicts where they interact with human activities.