Great-tailed Grackles are a large, conspicuous species of blackbird found across much of North and South America. With their long tails, yellow eyes, and jet black feathers, these birds are unmistakable. But just how big do Great-tailed Grackles get?
Wingspan
One of the most noticeable features of Great-tailed Grackles is their large wingspan. When in flight, these birds extend their wings to stabilize and maneuver. An adult male Great-tailed Grackle has an average wingspan of around 20 inches (51 cm). Females are slightly smaller, with an average wingspan of 18 inches (46 cm). The wingspan range for the species as a whole is approximately 16-22 inches (40-56 cm). This puts them on the larger end of blackbirds in terms of wingspan.
Body Length
Looking just at the body, Great-tailed Grackles are also relatively large. Males average around 15 inches (38 cm) in length from the tip of the bill to the end of the tail. Females are slightly smaller, averaging around 13 inches (33 cm) long. Overall, the body length range for Great-tailed Grackles is approximately 11-17 inches (28-43 cm).
Measurement | Male Average | Female Average | Range |
---|---|---|---|
Wingspan | 20 in (51 cm) | 18 in (46 cm) | 16-22 in (40-56 cm) |
Body Length | 15 in (38 cm) | 13 in (33 cm) | 11-17 in (28-43 cm) |
Weight
When it comes to weight, male Great-tailed Grackles typically weigh around 6-7 ounces (180-200 grams) on average. Females weigh slightly less, averaging around 5 ounces (150 grams). Overall, Great-tailed Grackles can weigh between 4-8 ounces (110-230 grams). This makes them one of the heavier icterid species, or blackbird family of birds.
Tail Length
As their name implies, Great-tailed Grackles have exceptionally long tails. Their tails make up around half of their total body length. An adult male’s tail averages around 7-8 inches long (18-20 cm). Female tails are slightly shorter, averaging 6-7 inches (15-18 cm). Combined, the overall tail length for Great-tailed Grackles ranges from 5-10 inches (13-25 cm). The long graduated shape of the tail is a key field mark for identifying this species.
Differences Between Males and Females
In most measurements, male Great-tailed Grackles are distinctly larger than females. This size difference is most apparent in the tail length, where males may have tails up to 3 inches longer than females. The males’ larger size is likely tied to their elaborate courtship displays, where they fan out their tails and wings to attract mates. The smaller female size may be advantageous for nesting and caretaking duties.
Head Size
In addition to having an elongated tail, Great-tailed Grackles have a relatively large head size compared to their body. Average head length for the species is around 3-4 inches (7-10 cm). With their stout, conical bill and puffy throat feathers, the head of a Great-tailed Grackle is strikingly prominent.
Leg Length
Great-tailed Grackles have medium-long legs that give them a lanky, slender profile. Their legs span around 3-4 inches (7-10 cm) on average. This adaptations gives them wading ability in shallow water to forage for food. However, their legs are not as exaggerated as other wading birds like cranes or herons.
Comparison to Other Birds
When compared to other common blackbird species, the Great-tailed Grackle is distinctly larger. For example, the average Red-winged Blackbird has a total length of around 9.5 inches compared to the Great-tailed’s 15 inches. Below is a table comparing the Great-tailed Grackle’s size measurements with two other common icterid species:
Species | Total Length | Wingspan |
---|---|---|
Great-tailed Grackle | 15 in | 20 in |
Red-winged Blackbird | 9.5 in | 15 in |
Common Grackle | 12 in | 17 in |
As the table shows, the Great-tailed Grackle is significantly larger than the Red-winged Blackbird in both total length and wingspan. It is also larger overall than the Common Grackle, which is part of the same genus Quiscalus.
Skeleton Size
Like all birds, the Great-tailed Grackle has a lightweight, rigid skeleton adapted for flight. Their bones are pneumatic, meaning they are hollow and filled with air sacs. This allows them to minimize skeletal weight. The skull of a Great-tailed Grackle averages around 1.5 inches long. Their humerus bone, which connects the shoulder to the forewing, spans around 1.3 inches. Leg bones like the tibiotarsus average around 2.2 inches long. Overall, the skeletal structure is medium-sized and specially adapted for the bird’s aerial lifestyle.
Range of Sizes
While average measurements give a general idea of the species’ size, individual Great-tailed Grackles can vary across the normal range. The largest specimens tend to be found at the northern reaches of their range, following Bergmann’s rule that body size increases with latitude. Birds in temperate interior regions also run larger. The very smallest individuals are found in hot, humid tropical areas. Throughout their widespread range across Central and North America, there is considerable variation in size due to factors like habitat, climate, and nutrition during development. But overall, the Great-tailed Grackle remains one of the most physically imposing icterid species no matter where it occurs.
Changes Over Lifespan
Great-tailed Grackles go through dramatic changes in size over their lifespan. Hatchlings weigh only about 1 ounce and are just 3 inches long in the first few days. But they grow incredibly quickly on a protein-rich diet fed by their parents. After just two weeks they are 7 inches long and weigh 3 ounces. By one month of age the young birds are full adult size. First year males look similar to adult females, with shorter tails and less iridescent plumage. By their second year they achieve full mature size and their long tail streamers used for breeding displays.
Conclusion
With its lanky profile, impressive wingspan, and outrageously long graduated tail, the Great-tailed Grackle stands out as the bulkiest icterid bird in its range. Males average around 15 inches long with a 20 inch wingspan, but can reach up to 17 inches long in some populations. Females are smaller, but still very large for a blackbird. No matter what region they live in, Great-tailed Grackles are unmistakable giants among their bird family. Their large size aids their scansorial lifestyle as they forage on the ground and in shallow water for varied food. Next time you see a huge, noisy flock of blackbirds, look for the giant tails waving above the crowd – chances are it will be a squadron of Great-tailed Grackles.