Electronic Supplementary Material – Online Resource 1

How much is that birdie in my backyard? A cross-continental economic valuation of native urban songbirds

Barbara Clucas1, Sergey Rabotyagov2, and John M. Marzluff2

1 Department of Wildlife, Humboldt State University, One Harpst Street, Arcata, CA, 95521 USA; email: ; fax: 001 707 826 4060

2School of Environmental and Forest Sciences, Box 352100, University of Washington, Seattle, Washington, 98195, USA

Table S1. Study site characteristics for Seattle and Berlin and survey sample sizes.

City / Study Site / Urban Level / Human Density (average resident/ha)a / Number of Successful Surveys1 / Number of Declined Surveys2 / Total Number of Residences Attempted3
Seattle / Belltown / Urban / 129 / 26 / 17 / 65
Capitol Hill / Urban / 129 / 25 / 15 / 135
Ravenna / Dense Suburban / 37 / 28 / 13 / 96
Laurelhurst / Dense Suburban / 24 / 25 / 9 / 93
Somerset / Light Suburban / 14 / 25 / 12 / 88
Westwood / Light Suburban / 11 / 29 / 11 / 85
Maltby / Rural / 2 / 25 / 10 / 92
Duvall / Rural / 8 / 26 / 8 / 94
Berlin / Moabit / Urban / 350 / 52 / - / -
Kreuzberg / Urban / 400 / 50 / - / -
Gropiusstadt / Housing Project / 151 / 50 / - / -
Märkisches Viertel / Housing Project / 175 / 51 / - / -
Mariendorf / Dense Suburban / 45 / 50 / - / -
Karlshorst / Dense Suburban / 77 / 50 / - / -
Rudow / Light Suburban / 49 / 50 / - / -
Dahlem / Light Suburban / 22 / 50 / - / -
Lübars / Rural / 15 / 31 / - / -
Blankenfelde / Rural / 9 / 26 / - / -

aSeattle: American FactFinder; Berlin: Senate Department for Urban Development (FIS Broker:

1Number of residents that agreed to do survey and survey successfully completed

2Number of residents that were asked to do survey and resident declined

3Total number of residences that were attempted (includes no responses, e.g., not home)

Variable definitions for Tables S2-S6

Variable Name / Variable Definition
bothered by birds / Bothered by birds noise “somewhat” or “very much”
notice birds / Notice birds at least weekly
female / Gender (1 = female, 0 = male)
age / Age (continuous scale)
popdens / Human population density
fulltime / Employed full time
green / Conservation/environmental issues most or very important
conservationorg / Membership in a conservation organization
own / Housing ownership (1 = own, 0 = rent)
educyr / Years of education
ageeduc / Age by education interaction
foreignborn / Foreign-born
incimp / Income category
Annual expenditure / Annual expenditure on bird food
BSA count / Number of bird-supporting activities

Table S2. Seattle unweighted sample summary statistics

Variable / N / Mean / Std Dev / Minimum / Maximum
bothered by birds
notice birds
female
age
popdens
fulltime
green
conservationorg
own
educyr
ageeduc
foreignborn
incimp
Annual expenditure
BSA count
/ 209
209
209
209
209
209
209
209
209
206
206
209
209
159
209
/ 0.0765550
0.9856459
0.5837321
49.6411483
43.7416268
0.3110048
0.5741627
0.1770335
0.7751196
15.7475728
780.7961165
0.1148325
3.9234450
49.1761006
1.1866029
/ 0.2665225
0.1192311
0.4941226
17.2996896
49.5998434
0.4640162
0.4956565
0.3826135
0.4185059
1.8569235
293.1169869
0.3195852
1.7796595
146.2557382
1.3511435
/ 0
0
0
18.0000000
2.0000000
0
0
0
0
12.0000000
216.0000000
0
1.0000000
0
0
/ 1.0000000
1.0000000
1.0000000
90.0000000
129.0000000
1.0000000
1.0000000
1.0000000
1.0000000
18.0000000
1620.00
1.0000000
7.0000000
1200.00
4.0000000

Table S3. Seattle weighted sample summary statistics (using post-stratification weights). Note: since post-stratification weighting required assigning an observation to a post-stratification category, item non-response (e.g., age, gender) has reduced sample size by a small number.

Variable / N / Mean / Std Dev / Minimum / Maximum
bother
notice
female
age
popdens
fulltime
green
conservationorg
Own
Educyr
Ageeduc
Foreignborn
Incimp
Annual expenditure
BSA count
/ 206
206
206
206
206
206
206
206
206
206
206
206
206
158
206
/ 0.0735777
0.9939558
0.5035620
43.6394180
32.2845103
0.4392894
0.4622197
0.0936038
0.7385422
13.9511846
608.8125903
0.0819865
3.6707787
52.2648364
1.2198761
/ 0.2737934
0.0812827
0.5243296
17.4550446
50.3893602
0.5204633
0.5228439
0.3054578
0.4608227
1.9432981
259.7568145
0.2877008
1.7011935
175.3668853
1.3364801
/ 0
0
0
18.0000000
2.0000000
0
0
0
0
12.0000000
216.0000000
0
1.0000000
0
0
/ 1.0000000
1.0000000
1.0000000
90.0000000
129.0000000
1.0000000
1.0000000
1.0000000
1.0000000
18.0000000
1620.00
1.0000000
7.0000000
1200.00
4.0000000

Table S4. Berlin unweighted sample summary statistics

Variable / N / Mean / Std Dev / Minimum / Maximum
bothered
notice birds
female
age
PopDensity
fulltime
green
enviroorg
own
education_years
ageeduc
foreign
incimp
Annual expenditure
BSA count
/ 460
460
458
457
460
460
460
460
459
451
449
460
460
459
460
/ 0.1413043
0.9978261
0.6069869
55.1291028
141.3565217
0.1804348
0.8000000
0.0478261
0.4771242
12.0443459
655.3363029
0.0521739
3.1258261
11.2638981
1.1500000
/ 0.3487145
0.0466252
0.4889538
18.4553386
135.5324329
0.3849679
0.4004355
0.2136304
0.5000214
2.7475699
255.7005530
0.2226197
1.3964853
23.8693351
1.1942582
/ 0
0
0
16.0000000
9.0000000
0
0
0
0
9.0000000
144.0000000
0
1.0000000
0
0
/ 1.0000000
1.0000000
1.0000000
96.0000000
400.0000000
1.0000000
1.0000000
1.0000000
1.0000000
16.0000000
1536.00
1.0000000
7.0000000
224.0000000
4.0000000

Table S5. Berlin weighted sample summary statistics (using post-stratification weights). Note: since post-stratification weighting required assigning an observation to a post-stratification category, item non-response (e.g., age, gender) has reduced sample size by a small number.

Variable / N / Mean / Std Dev / Minimum / Maximum
bothered
notice birds
female
age
popdensity
fulltime
green
conservationorg
own
education_years
ageeduc
foreign
incimp
Annual expenditure
BSA count
/ 455
455
455
455
455
455
455
455
454
447
447
455
455
454
455
/ 0.1770261
0.9972057
0.5299880
49.9099412
119.1160282
0.2311058
0.7729817
0.0401053
0.4469304
12.8237490
637.0702392
0.0520204
3.6282334
11.3666712
1.1745659
/ 0.3516952
0.0486385
0.4598776
16.0156762
126.0658954
0.3884127
0.3859844
0.1807871
0.4579153
2.4742517
237.2234773
0.2046166
1.4644451
19.9424320
1.1152823
/ 0
0
0
16.0000000
9.0000000
0
0
0
0
9.0000000
144.0000000
0
1.0000000
0
0
/ 1.0000000
1.0000000
1.0000000
96.0000000
400.0000000
1.0000000
1.0000000
1.0000000
1.0000000
16.0000000
1536.00
1.0000000
7.0000000
224.0000000
4.0000000

Table S6. Participation and levels of participation in bird-supporting activities equation estimates for Seattle. Note: in terms of interpreting the coefficients, the software used estimates of the impact of covariates on the probability of zero outcomes, so, in the participation equations, negative coefficients are interpreted as having a positive impact on the decision to engage in bird-supporting activities N = 206; log likelihood = -144.75).

Participation / Level of Participation
Variable description / Estimate / Standard Error / Pr > ChiSq / Estimate / Standard Error / Pr > ChiSq
Intercept / -1.2036 / 0.8931 / 0.1778 / -1.1055 / 0.3202 / 0.0006
Gender = Female / - / - / - / 0.3106 / 0.1512 / 0.0400
Age / - / - / - / 0.0226 / 0.0045 / <.0001
Population density / 0.0225 / 0.0067 / 0.0008 / - / - / -
Employed Fulltime / 2.0883 / 0.7566 / 0.0058 / 0.6996 / 0.1874 / 0.0002
Positive conservation attitude / -1.6278 / 0.7612 / 0.0325 / - / - / -
Own home / -1.3482 / 0.6946 / 0.0523 / - / - / -

Table S7. Participation and levels of participation in bird-supporting activities equation estimates for Berlin. Note that in terms of interpreting the coefficients, the software used estimates of the impact of covariates on the probability of zero outcomes, so, in the participation equations, negative coefficients are interpreted as having a positive impact on the decision to engage in bird-supporting activities (N = 448; log likelihood = -331.04).

Participation / Level of Participation
Parameter / Estimate / Standard Error / Pr > ChiSq / Estimate / Standard Error / Pr > ChiSq
Intercept / 16.1733 / 8.0925 / 0.0457 / -0.1898 / 0.2617 / 0.4683
Bothered by birds / 4.7253 / 2.9628 / 0.1107 / 0.2711 / 0.1206 / 0.0246
Age / -0.6442 / 0.2888 / 0.0257 / - / - / -
Population density / 0.0192 / 0.0087 / 0.0277 / -0.0024 / 0.0007 / 0.0002
Positive conservation attitude / -1.8211 / 1.1526 / 0.1141 / 0.2419 / 0.1379 / 0.0793
Conservation organization membership / - / - / - / 0.5012 / 0.1644 / 0.0023
Own home / -5.2158 / 2.7848 / 0.0611 / 0.2962 / 0.1120 / 0.0082
Years of education / -1.5691 / 0.8131 / 0.0536 / -0.0382 / 0.0225 / 0.0891
Age* education interaction / 0.0466 / 0.0215 / 0.0302 / 0.0007 / 0.0003 / 0.0102
Income level / - / - / - / 0.0620 / 0.0344 / 0.0715

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