Steller’s jays and blue jays are two species of jays found in North America. Jays are a type of corvid, which is the family of birds that includes crows, ravens, and magpies. Both Steller’s jays and blue jays have predominantly blue and black plumage, which can lead some people to confuse the two species. However, there are distinct differences in size and distribution between Steller’s jays and blue jays. Determining which species is larger requires looking at various measurements of the birds. By comparing their lengths, wingspans, weights, and other physical characteristics, we can get a clear answer to the question of whether Steller’s jays are bigger than blue jays.
Ranges and Habitats
To understand the size differences between these two jays, it is helpful to first look at where each species lives. This gives us clues about how their sizes may have adapted to their environments.
Steller’s Jay Range and Habitat
Steller’s jays are native to the forests of western North America. Their range extends along the Pacific Coast from southern Alaska down through British Columbia, Washington, Oregon, and California. They are also found in the mountain regions of the western interior, including parts of Idaho, Montana, Wyoming, Colorado, Utah, and New Mexico.
Within their range, Steller’s jays occupy coniferous forests and mixed evergreen forests. They thrive at medium to high elevations where pine trees and other conifers dominate. Their preferred habitat includes dense stands of trees, which provide ample places to hide nests and store food.
Blue Jay Range and Habitat
In contrast, blue jays occupy a broad swath of eastern and central North America. Their range stretches from southern Canada down through the eastern and central United States to Texas and Florida. A small disjunct population also exists in New Mexico and Arizona.
Blue jays reside in deciduous forests across most of their range. Unlike Steller’s jays, they prefer broadleaf trees like oaks, maples, and beeches. Blue jays adapt readily to human settlements and are common in parks, suburbs, and backyards with mature trees. They do well in more open and fragmented forests.
The habitat differences between these species provide initial clues about their sizes. Steller’s jays likely evolved larger sizes in the dense western forests where their range overlaps with other big corvids like ravens. Meanwhile, the more open deciduous woods of blue jays’ range favors smaller, more agile birds.
Length Comparisons
One basic way to compare the sizes of birds is to look at their total body lengths, usually measured from the tip of the bill to the tip of the tail. The average body lengths of Steller’s jays and blue jays are:
Steller’s Jay:
– Total length: 30-34 cm (12-13 inches)
Blue Jay:
– Total length: 22-30 cm (9-12 inches)
These typical length ranges show that Steller’s jays reach larger overall sizes than blue jays. The maximum total length of a Steller’s jay is 34 cm (13 in), while blue jays max out at around 30 cm (12 in). Even the minimum recorded length of a Steller’s jay is 30 cm (12 in), equal to the maximum for blue jays.
Clearly, Steller’s jays are longer birds from head to tail. Their greater size is likely an adaptation to living in dense coniferous forests, where the maneuverability of smaller birds like blue jays would be limited. The longer tails and wings of Steller’s jays let them fly smoothly between the tall, closely packed trees of their habitat.
Wingspan Comparison
In addition to total length, wingspan is another useful measure for comparing bird sizes. A bird’s wingspan correlates with the overall surface area of its wings. Larger wings allow birds to generate more lift and propulsion with each flap.
Here are the average wingspans for Steller’s jays and blue jays:
Steller’s Jay:
– Wingspan: 34-40 cm (13-16 inches)
Blue Jay:
– Wingspan: 22-30 cm (9-12 inches)
Again, we see that there is considerable overlap between the species, but Steller’s jays reach substantially broader wingspans on the high end. The maximum recorded wingspan for Steller’s jays is 40 cm (16 in), while blue jay wingspans top out at around 30 cm (12 in).
The broader wingspans of Steller’s jays are another adaptation for maneuvering through dense forests. Their larger wing surface area provides extra lift and control as they fly between narrowly spaced trees. Meanwhile, blue jays do not need such wide wingspans in the more open deciduous forests they inhabit.
Weight Comparison
Comparing the weights of Steller’s jays and blue jays offers further insight into their size differences. Heavier birds require more muscle power and wing strength to get off the ground. Avian weight also tends to correlate with overall bulk.
Here are the typical weight ranges for each species:
Steller’s Jay:
– Weight: 140-170 g (5-6 oz)
Blue Jay:
– Weight: 70-100 g (2.5-3.5 oz)
The weight ranges reveal the Steller’s jay as a noticeably heftier bird than the blue jay. At 140-170 g, Steller’s jays are around twice as heavy as blue jays, which weigh just 70-100 g. The bulkier body of Steller’s jays adds to their advantage in length and wingspan.
Interestingly, some key measurements overlap substantially between the two species. But the weights demonstrate that Steller’s jays have much more overall mass and volume than blue jays. The Steller’s jay’s heavier build is well-suited to its coniferous mountain habitat.
Tail Length Comparison
Tails play an important role in avian flight control and maneuvering. Comparing tail lengths is another way to elucidate the size differences between bird species.
Here are the typical tail lengths for Steller’s jays and blue jays:
Steller’s Jay:
– Tail length: 13-15 cm (5-6 inches)
Blue Jay:
– Tail length: 10-15 cm (4-6 inches)
The numbers reveal a high overlap in tail lengths between the two jays. Blue jays have tails spanning 10-15 cm long, while Steller’s jays have slightly longer tails of 13-15 cm. However, the ranges mostly coincide.
The similar tail proportions make sense given the importance of tails in flight steering. Both species need adequate tail surfaces to maneuver through vegetation. The tails may show less divergence in length than wingspans due to shared needs for aerial agility.
However, the tails of Steller’s jays do appear slightly longer on average. This grants them superior control as they weave through narrowly spaced conifers. It is another adaptation to life in dense Pacific forests.
Bill Size Comparison
Bird bills show high specialization based on feeding habits and diet. Comparing bill sizes and shapes can provide more clues to differences between bird species.
Here are the bill dimensions for Steller’s jays and blue jays:
Steller’s Jay:
– Bill length: 2-3 cm (0.75-1 inch)
– Bill depth at base: 1-1.5 cm (0.4-0.6 inches)
Blue Jay:
– Bill length: 2-3 cm (0.75-1 inch)
– Bill depth at base: 0.8-1 cm (0.3-0.4 inches)
Interestingly, the bill lengths hardly differ at all between Steller’s jays and blue jays. Both species have beaks ranging from 2-3 cm long from the tip to where they join the skull.
However, Steller’s jays have noticeably deeper and bulkier bills. Their beaks measure 1-1.5 cm deep at the base, while blue jay bills are just 0.8-1 cm deep. This corresponds to the overall bulkier body size of Steller’s jays.
The thick bill of Steller’s jays is likely an adaptation for cracking hard nuts and seeds. These birds often stash pine nuts and acorns in tree crevices, then retrieve them later using their powerful bills. The slimmer bill of blue jays reflects a more omnivorous diet, including fruits, insects, and small vertebrates.
Comparison of Foot and Leg Size
The feet and legs of birds are another determinant of overall size and proportions. Larger feet help maintain stability on the ground or when perching. Comparing leg dimensions provides more clues to the size differences between Steller’s jays and blue jays.
Here are typical leg and foot sizes for each species:
Steller’s Jay:
– Tarsus length: 3.8-4.5 cm (1.5-1.75 inches)
– Total toe length: 5-6 cm (2-2.5 inches)
Blue Jay:
– Tarsus length: 2.5-3.5 cm (1-1.4 inches)
– Total toe length: 4-5.5 cm (1.6-2.2 inches)
Once again, the data show the Steller’s jay as the larger bird overall. Steller’s jays have longer tarsi (lower legs) spanning 3.8-4.5 cm, compared to just 2.5-3.5 cm in blue jays. Their total toe length is also greater at 5-6 cm, versus 4-5.5 cm in blue jays.
The proportionally longer legs and feet of Steller’s jays provide greater stability as they clamber through conifer branches high in the canopy. Meanwhile, blue jays do not need such robust legs and feet when moving through more open deciduous woods. The leg measurements confirm the consistently bulkier build of Steller’s jays.
Comparison of Volumes and Density
The final measures that elucidate the size difference between Steller’s jays and blue jays are their overall volumes and densities. Volume calculations account for the three-dimensional space occupied by the birds. Density approximates how massive the two jays are relative to their volumes.
To estimate volume, we can treat each bird’s body as an ellipsoid, or stretched sphere shape. The formula is:
Volume = (4/3) * π * (width/2) * (depth/2) * (length/2)
Using the midpoints of typical length, wingspan, and weight measurements yields the following volume estimates:
Steller’s Jay:
– Volume: Around 225 cubic cm
– Density: Around 0.75 g/cubic cm
Blue Jay:
– Volume: Around 110 cubic cm
– Density: Around 0.9 g/cubic cm
The calculations show that Steller’s jays occupy roughly twice the overall volume of blue jays. However, blue jays actually have higher density, reflecting their more compact, streamlined forms.
These measurements provide additional perspective on the size differences between the two species. The much greater volume of Steller’s jays confirms their bulkier build adapted to mountain forests. But the density figures show blue jays are more sleekly built for mobility.
Summary Size Comparison
All the physical measurements point to the Steller’s jay as consistently larger in nearly every dimension. Here is a summary table highlighting the size differences between the two species:
Measurement | Steller’s Jay | Blue Jay |
---|---|---|
Length | 30-34 cm | 22-30 cm |
Wingspan | 34-40 cm | 22-30 cm |
Weight | 140-170 g | 70-100 g |
Tail Length | 13-15 cm | 10-15 cm |
Bill Size | Longer and deeper | Shorter and more slender |
Legs and Feet | Longer | Shorter |
Volume | ~225 cm3 | ~110 cm3 |
The Steller’s jay consistently has greater dimensions, including length, wingspan, weight, bill size, and leg size. The only measurement with much overlap is tail length, where both species share similar aerodynamic needs. Overall, the typical Steller’s jay is clearly the larger bird compared to the blue jay.
Conclusion
Based on a detailed look at their physical measurements and characteristics, Steller’s jays are distinctly larger than blue jays. Steller’s jays exceed blue jays in overall length, wingspan, weight, bill size, and leg dimensions. These greater size parameters reflect adaptations by Steller’s jays for maneuvering among dense coniferous forests. In contrast, blue jays occupy more open deciduous habitats where smaller builds are favored. By comparing all aspects of their anatomy, it is clear Steller’s jays are the larger species between the two similar-looking birds. Careful measurements provide the definitive answer that Steller’s jays are indeed bigger than their blue cousins.