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.

Posted by truthseqr truthseqr, September 29, 2018 11:24 PM

Observations

Photos / Sounds

What

Great Horned Owl (Bubo virginianus)

Observer

truthseqr

Date

September 24, 2018 02:18 PM PDT

Description

Feather: Great Horned Owl

Length: approx. 2 in (5 cm)

Pattern: Barred

Feather Type: Breast feather

Reference:

Tags

Photos / Sounds

What

Great Horned Owl (Bubo virginianus)

Observer

truthseqr

Date

September 24, 2018 02:22 PM PDT

Description

Feather
Species: Great Horned Owl

Length: ~3 in (7.6 cm)

Pattern: Barred

Placement:

Reference:

Tags

Photos / Sounds

What

Great Horned Owl (Bubo virginianus)

Observer

truthseqr

Date

September 24, 2018 02:26 PM PDT

Description

Owl pellet 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:
https://www.inaturalist.org/observations/8242916

Photos / Sounds

What

Great Horned Owl (Bubo virginianus)

Observer

truthseqr

Date

September 24, 2018 02:33 PM PDT

Description

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

Tags

Photos / Sounds

What

Great Horned Owl (Bubo virginianus)

Observer

truthseqr

Date

September 24, 2018 02:40 PM PDT

Description

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

Tags

Photos / Sounds

What

Great Horned Owl (Bubo virginianus)

Observer

truthseqr

Date

September 24, 2018 02:46 PM PDT

Description

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)

Tags

Photos / Sounds

What

Great Horned Owl (Bubo virginianus)

Observer

truthseqr

Date

September 24, 2018 02:47 PM PDT

Description

Feather
Species: Great Horned Owl

Length: ~2 in (5 cm)

Pattern: Mottled

Feather Type: Breast feather

Reference:

Tags

Photos / Sounds

What

Great Horned Owl (Bubo virginianus)

Observer

truthseqr

Date

September 24, 2018 02:31 PM PDT

Description

Owl pellet 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

Photos / Sounds

What

Great Horned Owl (Bubo virginianus)

Observer

truthseqr

Date

September 24, 2018 03:25 PM PDT

Description

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

Tags

Photos / Sounds

What

Great Horned Owl (Bubo virginianus)

Observer

truthseqr

Date

September 24, 2018 03:32 PM PDT

Description

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

Tags

Photos / Sounds

What

Red-tailed Hawk (Buteo jamaicensis)

Observer

truthseqr

Date

September 24, 2018 03:36 PM PDT

Description

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!

Tags

Photos / Sounds

What

North American Barn Owl (Tyto alba ssp. pratincola)

Observer

truthseqr

Date

September 24, 2018 03:43 PM PDT

Description

Feather: Barn Owl, female

Length: approx. 5 in (12.7 cm)

Pattern: Barred

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

Tags

Photos / Sounds

What

Red-tailed Hawk (Buteo jamaicensis)

Observer

truthseqr

Date

September 25, 2018 09:26 AM PDT

Description

Feathers: Red-tailed Hawk

Length: the longest one is ~5 in (12.7 cm)

Pattern: Barred

Feather Type: body feathers

Reference:

Tags

Photos / Sounds

What

Red-tailed Hawk (Buteo jamaicensis)

Observer

truthseqr

Date

September 25, 2018 09:27 AM PDT

Description

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

Tags

Photos / Sounds

What

Red-tailed Hawk (Buteo jamaicensis)

Observer

truthseqr

Date

September 25, 2018 09:27 AM PDT

Description

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

Tags

Photos / Sounds

What

Red-tailed Hawk (Buteo jamaicensis)

Observer

truthseqr

Date

September 25, 2018 09:28 AM PDT

Description

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:

Tags

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!!

Posted by truthseqr about 4 years ago (Flag)

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.

Posted by chartuso about 4 years ago (Flag)

Wow - thank you so much for this information, @chartuso! I really appreciate it.

Posted by truthseqr about 4 years ago (Flag)

Add a Comment

Sign In or Sign Up to add comments