Blue jays and scrub-jays are two similar but distinct species of jays found in North America. While they share some characteristics, there are key differences between the two.
Appearance
The most noticeable difference between blue jays and scrub-jays is their plumage. Blue jays have brilliant blue upperparts with a white underside and black necklace across the throat. Their wings and tail are blue with black bars and bright white spots. Scrub-jays have more subdued blue upperparts, a light gray underside, and a blue necklace across the throat. Their wings and tail are blue with faint black barring.
In terms of size, blue jays are slightly larger on average. Blue jays measure 22-30 cm (9-12 inches) long with a 34-43 cm (13-17 inch) wingspan. Scrub-jays are 21-24 cm (8-9 inches) long with a 32-37 cm (13-15 inch) wingspan.
Blue jays have a crest on top of their head that can be raised and lowered. Scrub-jays lack a crest.
Geographic Range
Blue jays have a much wider geographic range than scrub-jays across North America:
- Blue jays are found throughout the eastern and central United States as far west as Texas, Colorado, and Montana.
- Scrub-jays are found in the western United States from Washington to California and south into Mexico.
- There is limited overlap between the two species in parts of Colorado, New Mexico, and Texas.
Habitat
The different geographic ranges of blue jays and scrub-jays means they occupy different habitats:
- Blue jays are found in deciduous and mixed forests across eastern North America.
- Scrub-jays inhabit oak forests, pine-oak woodlands, and chaparral habitats of the western United States.
Within their ranges, both species adapt readily to human settlements and can be found in parks, suburban neighborhoods, and backyards.
Diet
Blue jays and scrub-jays are omnivores that eat a varied diet:
- Both eat nuts, seeds, fruits, berries, acorns, grain, and insects.
- Blue jays sometimes prey on eggs and nestlings, while scrub-jays rarely do.
- Blue jays often visit bird feeders, while scrub-jays rarely visit feeders.
A key difference is that scrub-jays store food caches for later use, while blue jays rarely do. Scrub-jays have specialized spatial memory to recover thousands of caches over the course of months.
Behavior
Blue jays and scrub-jays exhibit some behavioral differences:
- Blue jays are more aggressive than scrub-jays and known for raiding nests and taking eggs and nestlings.
- Scrub-jays are not as aggressive toward other birds.
- Blue jays are intelligent and frequently play tricks on other animals.
- Scrub-jays are also intelligent, but less mischievous than blue jays.
Both species are noisy and have a wide range of vocalizations used to communicate and warn of predators.
Breeding
Blue jays and scrub-jays build nests and breed at similar times of the year:
- Breeding season is March through July.
- Females build a nest of twigs, bark, roots, and moss in a tree or shrub.
- Females lay 3-6 eggs and incubate them for 16-18 days.
- Young fledge from the nest at 17-21 days old.
A difference is that blue jays are monogamous while scrub-jays are mostly monogamous but occasionally polygamous.
Species Classification
Blue jays and scrub-jays are classified into different genera, species, and subspecies:
Species | Genus | Species | Subspecies |
---|---|---|---|
Blue jay | Cyanocitta | Cyanocitta cristata | C. c. cristata C. c. bromia C. c. cyanotephra |
Scrub-jay | Aphelocoma | Aphelocoma californica | A. c. californica A. c. woodhouseii A. c. grisea |
The two species diverged evolutionarily 8-10 million years ago within the Corvidae bird family.
Status and Threats
Both blue jays and scrub-jays have large populations and are classified as Least Concern by the IUCN Red List. However, differences include:
- Blue jay populations are stable or increasing across their range.
- Some scrub-jay subspecies have experienced population declines due to habitat loss.
- Blue jays adapt readily to human development.
- Scrub-jays are sensitive to fragmentation in scrub habitats.
Key Differences
In summary, here are some of the key differences between blue jays and scrub-jays:
Trait | Blue Jay | Scrub-Jay |
---|---|---|
Plumage | Brilliant blue with black necklace | More subdued blue with blue necklace |
Range | Eastern and central North America | Western North America |
Habitat | Deciduous and mixed forests | Oak and pine-oak woodlands |
Diet | Omnivorous, visits feeders | Omnivorous, caches food |
Behavior | Intelligent, aggressive, mischievous | Intelligent, less aggressive |
Breeding | Monogamous | Mostly monogamous, occasionally polygamous |
Status | Least Concern, populations stable | Least Concern, some declines |
Conclusion
In conclusion, while blue jays and scrub-jays share similarities as members of the Corvidae family, they are distinct species with notable differences in appearance, range, habitat, behavior, breeding systems, and conservation status. Blue jays occupy deciduous forests in the east, while scrub-jays inhabit oak and pine woodlands in the west. Scrub-jays are more specialized in their habitat needs and some subspecies are declining. Understanding the similarities and differences between the two provides insights into the diversity of North America’s amazing jay species.