Madrona Marsh/Urban

Table of
Contents:

Urban Environments:
Urban Wildlife Surveys and Assessment.

Hollywood Hills-Runyon

We visited three sites to examine urban environments: Holmby Park, Westdale, and the Madrona Marsh. The urban wildlife at these sites is compared and evaluated with numerous techniques including the Shannon-Wiener Diversity Index, Jaccard's Similarity Index and behavioral studies. Vegetation is assessed with the line-intercept method.
Stop 1- Holmby Park
Holmby Park is a urban park in Westwood. This beautiful park is unique because it does not have playing fields. It does have a putting green and open spaces. We examined the vegetation and discussed the landscaping. Some of the plants are exotic- pampas grass.
I conducted point counts at 5 sites and counted birds observed within 50 meters of the point. I observed 13 species of birds in the park (and 2 species flying over the park that are not included in the calculations). I calculated the density of each species of birds in Holmby Park using the formula given by Prof. Walter.

Table 1. Density of each species observed at Holmby Park.

Density of pairs-Holmby Park
Species	Territories	Pairs/hectare
American Crow	3.5	89.1
American Goldfinch	1.5	38.2
American Robin	0.5	12.7
Anna's Hummingbird	0.5	12.7
Black Phoebe	2.5	63.7
House Finch	1.5	38.2
House Sparrow	12	305.6
Mourning Dove	0.5	12.7
Northern Mockingbird	0.5	12.7
Song Sparrow	3.5	89.1
Western Tanager	0.5	12.7
Wilson's Warbler	0.5	12.7
Yellow Warbler	1	25.5
Number of territories	28.5
Species Richness = 1

Stop 2 - Westdale
Westdale is a neighborhood in which birds have been surveyed for many years. Repeating surveys over a large temporal scale allows population trends and spatial patterns to be evaluated. These surveys have revealed the decline of American Robin populations in this neighborhood.
Habitats:
Corinth Avenue has large yards with the dominant tree being bottlebrush. Many of the yards contained small fences with a lot of vegetation around them. This created a structurally diverse habitat in which shrubby vegetation (not just grass) extended nearly to the street. Purdue Avenue also had large yards but few of these had fences and/or shrubby vegetation extending to the street, specifically they were mostly grass. The dominant tree is golden ram and this tree lined the street and provided extensive canopy cover that converged near the middle of the street. Butler Avenue was less manicured and less landscaped. These yards contained mainly grass and the dominant tree is Modesto Ash. The trees were fewer and sparser than on Corinth or Purdue, making the street feel more open overall. Colby Avenue was moderate in the degree of openness and the dominant tree is Jacaranda.
In summary, Purdue Avenue has the tall Golden Ram trees with simple lawns, Corinth Avenue had moderate sized Bottlebrush trees with complex lawns, Butler Avenue has few, sparse Modesto Ash trees and mostly simple yards, Colby Avenue has moderate sized Jacaranda trees and yards with a mix of landscaping.

Table 2. Density of each species observed in Westdale.

Density of Pairs - Westdale
Species	Territories	Pairs/hectare
House Finch	14.5	63.9
House Sparrow	24	105.7
European Starling	1.5	6.6
Northern Mockingbird	7.5	33.0
Mourning Dove	5.5	24.2
American Crow	10	44.1
Anna's Hummingbird	2.5	11.0
Bushtit	5	22.0
Western Tanager	1	4.4
Rock Dove	1.5	6.6
Parrot	1	4.4
Number of Territories	74
Species richness = 12

Methods

We conducted avian surveys in groups of four and described habitat components of each street. (Click here to view the map of the study site). Birds are censused on 4 streets in the Westdale neighborhood (see Table 2 for density calculations). This included walking down each street and mapping the location of each species observed. Efforts are made to determine the sex of each individual but this was very difficult due to monomorphic species and slow responses with binoculars. Consequently, all individuals are recorded and an estimate of the number of pairs/territories is obtained by dividing the total number by two.

Shannon-Wiener Diversity Index (H’)
Table 3. Results of Shannon-Wiener diversity index and the
Evenness index.

	Shannon-Wiener Holmby Park
Species	Pi	ln(pi)	H'
American Crow	0.123	-2.097	-0.258
American Goldfinch	0.053	-2.944	-0.155
American Robin	0.018	-4.043	-0.071
Anna's Hummingbird	0.018	-4.043	-0.071
Black Phoebe	0.088	-2.434	-0.213
House Finch	0.053	-2.944	-0.155
House Sparrow	0.421	-0.865	-0.364
Mourning Dove	0.018	-4.043	-0.071
Northern Mockingbird	0.018	-4.043	-0.071
Song Sparrow	0.123	-2.097	-0.258
Western Tanager	0.018	-4.043	-0.071
Wilson's Warbler	0.018	-4.043	-0.071
Yellow Warbler	0.035	-3.350	-0.118
H'	1.000	-40.990	1.946
Evenness Holmby Park	H'/ln(# species)	-0.759

	Shannon-Wiener Westdale
Species	Pi	ln(pi)	Pi[ln(pi)]
House Finch	0.196	-1.630	-0.319
House Sparrow	0.324	-1.126	-0.365
European Starling	0.020	-3.899	-0.079
Northern Mockingbird	0.101	-2.289	-0.232
Mourning Dove	0.074	-2.599	-0.193
American Crow	0.135	-2.001	-0.270
Anna's Hummingbird	0.034	-3.388	-0.114
Bushtit	0.068	-2.695	-0.182
Western Tanager	0.014	-4.304	-0.058
Rock Dove	0.020	-3.899	-0.079
Parrot	0.014	-4.304	-0.058
H'	1.000	-32.134	1.951
Evenness Westdale	H'/ln(# species)	-0.785

Comparison of Westdale and Holmby Park

The diversity of these two locations is remarkably similar (Holmby Park H’ = 1.946, Westdale H’ = 1.951). In fact, rounding could make them appear identical (1.95) but Westdale is a little more diverse than Holmby Park. It is important to note that these two locations are not identical as can bee seen by looking at the particular species in each sample -they are nearly equally diverse. The evenness index reveals that they are, in fact, different (Holmby Park, E = 0.759, Westdale, E = 0.785). But these two values are also similar with Westdale being slightly more even than Holmby Park. This demonstrates the importance of evaluating communities with more than one method.

Jaccard’s Similarity index
The Jaccard’s Index is equal to zero for two sites that are completely dissimilar. One indicates that two sites are completely similar. All three comparisons reveal that these sites are moderately similar.

Table 4. Jaccard’s Similarity Index compares three locations to
determine the similarity of two sites.

Jaccard's Similarity Index
Comparison (a*b)	j	a	b	j/(a+b-j)
Holmby x Westdale	7	13	11	0.412
Holmby x Burbank	6	13	13	0.300
Westdale x Burbank	8	11	13	0.500

From the evidence in the H’, the diversity index, E, the evenness index and j, the similarity index, I conclude that these three locations are moderately similar in diversity and evenness. Burbank is more similar to Westdale than to Holmby Park, Holmby Park is more similar to Westdale than to Burbank.

Last updated: April 12, 2004.