Owls and Hawks at Edenvale Garden Park
The other day my granddaughter and I went searching for feathers at Edenvale Garden Park near the Hayes Mansion. There were many feathers from two species of owls (Great Horned Owl and Barn Owl), a Red-tailed Hawk, and several other species of birds. We also found three owl pellets under a eucalyptus tree where I saw a great horned owl perched last year (https://www.inaturalist.org/observations/8242916). Last spring there were several Great Horned Owl offspring in this park (I didn't see them, but I talked to a couple who had seen them several times).
I'm wondering how three large predatory birds can live within a several yards of each other? They all appear to be nesting in a stand of eucalyptus trees in the northwestern section of the park.
This park has lots of California Ground Squirrels and Eastern Gray Squirrels (including the melanistic variety), so there is a plentiful food supply.
Several blocks away there is another park - Martial Cottle Park, part of which is an inner-city farm. There are Barn Owls and Great Horned Owls nesting in that park as well. A volunteer told me they had about a dozen owl chicks in one of the bird houses there last spring. However, the staff poison the ground squirrels at Martial Cottle Park because they damage the crops. Perhaps the owls from Martial Cottle Park fly the short distance to Edenvale Park to hunt.
Observations
Photos / Sounds
What
Great Horned Owl (Bubo virginianus)Observer
truthseqrDescription
Feather: Great Horned Owl
Length: approx. 2 in (5 cm)
Pattern: Barred
Feather Type: Breast feather
Reference:
Photos / Sounds
What
Great Horned Owl (Bubo virginianus)Observer
truthseqrDescription
Feather
Species: Great Horned Owl
Length: ~3 in (7.6 cm)
Pattern: Barred
Placement:
Reference:
Photos / Sounds
What
Great Horned Owl (Bubo virginianus)Observer
truthseqrDescription
Great Horned Owl pellet #6 with many small bones and fur. Eucalyptus leaf shows relative size.
Found under a eucalyptus tree where a Great Horned Owl is known to reside. Here are the observations for the owl that lives in this tree:
• https://www.inaturalist.org/observations/8242916
• https://www.inaturalist.org/observations/8210744
Contents:
a. (Perching Birds) https://www.inaturalist.org/observations/173145424
Photos / Sounds
What
Great Horned Owl (Bubo virginianus)Observer
truthseqrDescription
Feather: Great Horned Owl
Length: approx. 6 in (15 cm)
Pattern: Mottled
Feather Type:
Reference:
Note: Found near a eucalyptus tree where a Great Horned Owl is known to reside:
https://www.inaturalist.org/observations/8242916
Photos / Sounds
What
Great Horned Owl (Bubo virginianus)Observer
truthseqrDescription
Feather: Great Horned Owl
Length: approx. 4 in (10 cm)
Pattern: Barred
Colors: White/Brown/Yellow/Gray
Feather Type: Under-tail Covert
Reference:
- "Bird Feathers: A Guide to North American Species", S. David Scott and Casey McFarland, (Stackpole Books, 2010, pp. 200-201)
Found near a eucalyptus tree where a Great Horned Owl is known to reside:
https://www.inaturalist.org/observations/8242916
Photos / Sounds
What
Great Horned Owl (Bubo virginianus)Observer
truthseqrDescription
Feather
Species: Great Horned Owl
Length: ~4 in (10 cm)
Colors: White/Brown/Yellow/Gray
Pattern: Barred
Feather Type: Breast feather
Reference:
- "Bird Feathers: A Guide to North American Species", S. David Scott and Casey McFarland, (Stackpole Books, 2010, pp. 200-201)
Photos / Sounds
What
Great Horned Owl (Bubo virginianus)Observer
truthseqrDescription
Feather
Species: Great Horned Owl
Length: ~2 in (5 cm)
Pattern: Mottled
Feather Type: Breast feather
Reference:
Photos / Sounds
What
Great Horned Owl (Bubo virginianus)Observer
truthseqrDescription
Great Horned Owl pellet #7 with many small bones and fur. Eucalyptus leaf can be used for sizing.
Found under a eucalyptus tree where a Great Horned Owl is known to reside:
• https://www.inaturalist.org/observations/8242916
• https://www.inaturalist.org/observations/8210744
This owl pellet contained the remains of:
Old World Rat(s)
https://www.inaturalist.org/observations/173144404
Photos / Sounds
What
Great Horned Owl (Bubo virginianus)Observer
truthseqrDescription
Feather
Species: Great Horned Owl
Length: ~5 in (12.7 cm)
Pattern: Barred
Feather Type:
Note: Found near a eucalyptus tree where a Great Horned Owl is known to reside:
https://www.inaturalist.org/observations/8242916
Photos / Sounds
What
Great Horned Owl (Bubo virginianus)Observer
truthseqrDescription
Feather: Great Horned Owl
Length: approx. 6 in (15 cm)
Pattern: Barred
Placement: Tail
Reference: https://www.fws.gov/lab/featheratlas/feather.php?Bird=GHOW_tail
Note: Found near a eucalyptus tree where a Great Horned Owl is known to reside:
https://www.inaturalist.org/observations/8242916
Photos / Sounds
What
Red-tailed Hawk (Buteo jamaicensis)Observer
truthseqrDescription
Feather: Red-tailed Hawk
Length: approx. 10 inches (25 cm)
Color: Red/Rufous
Pattern: Dark bar across tip and white near base
Feather type: Tail feather (rectrices)
Reference:
https://www.fws.gov/lab/featheratlas/feather.php?Bird=RTHA_tail_adult_various
What an exciting find!
Photos / Sounds
What
North American Barn Owl (Tyto alba ssp. pratincola)Observer
truthseqrDescription
Feather: Barn Owl, female
Length: approx. 5 in (12.7 cm)
Pattern: Barred / Mottled
Placement: Secondary
Reference: https://www.fws.gov/lab/featheratlas/feather.php?Bird=BNOW_secondary_dkfemale
Note: Found near a eucalyptus tree where a Great Horned Owl is known to reside:
https://www.inaturalist.org/observations/8242916
Photos / Sounds
What
Red-tailed Hawk (Buteo jamaicensis)Observer
truthseqrDescription
Feathers: Red-tailed Hawk
Length: the longest one is ~5 in (12.7 cm)
Pattern: Barred
Feather Type: body feathers
Reference:
Photos / Sounds
What
Red-tailed Hawk (Buteo jamaicensis)Observer
truthseqrDescription
Feather: Red-tailed Hawk
Length: approx. 9 in (23 cm)
Color: Red/Rufous
Pattern: Mottled: Mostly unpatterned but with black stripe across tip some black spots and white near base.
Feather type: Tail feather (rectrices)
Reference:
https://www.fws.gov/lab/featheratlas/feather.php?Bird=RTHA_tail_adult_various
Note: We found this feather about 3-4 yards from the one we found yesterday:
https://www.inaturalist.org/observations/16900630
Photos / Sounds
What
Red-tailed Hawk (Buteo jamaicensis)Observer
truthseqrDescription
Red-tailed Hawk feather
Length: approx. 9 in (22.9 cm)
Color: Brown / White
Pattern: Barred
Feather Type: Secondary wing feather
Reference:
https://www.fws.gov/lab/featheratlas/feather.php?Bird=RTHA_secondary_adult
Photos / Sounds
What
Red-tailed Hawk (Buteo jamaicensis)Observer
truthseqrDescription
Feather: Red-tailed Hawk
Length: the longest one is approx. 5 in (12.7 cm)
Pattern: White with rufous spots
Placement: Body feather
Reference:
Note: These feathers were found under eucalyptus trees where a red-tailed hawk is known to reside:
Comments
@chartuso, I'm wondering if you can shed some light on this. Is it common for two different owl species to live in such close proximity to each other? It appears that a Barn Owl and a Great Horned Owl are both living in a stand of Eucalyptus trees in this small city park. There is also a large red-tailed hawk nesting in one of the Eucalyptus trees. It seems that these birds would fight over this territory. Please help me understand the interactions of these three species. Thanks!!
Thanks @truthseqr . Yes, it is not uncommon for multiple raptor species, including more than one diurnal species or more than one nocturnal species, to overlap. This can happen through resource partitioning, where the species have a food niche that does not overlap completely; for example, if one is a specialist and the other is a generalist. In some cases, size is important; for example, if there is competition for cavities for cavity-nesting species, different body size reduces effective competition for suitable nesting sites. Great Horned Owls are generalists in both their nesting substrate and their diet, whereas Barn Owls tend to be more specialised and rodents feature strongly in the diet. Having said that, Great Horned Owls will prey upon Barn Owls if given the chance. In addition, diurnal raptors and nocturnal raptors nest in close proximity but competition and interaction is reduced because of day-time budget.
Wow - thank you so much for this information, @chartuso! I really appreciate it.
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