S2. Data on melanization, T levels, and confounding variables used in the analyses

male melanization1 / melanin dichromatism2 / T “at molt”3 (ng/ml) / polygyny % / paternal incubation % / paternal feeding % / breeding latitude
species / taxon4 / references5
Acrocephalus scirpaceus / 0.000 / -0.702 / 0.1 / 12 / 50 / 47.6 / 4 / 49, 128
Acrocephalus seychellensis / 0.000 / -0.702 / 0 / 0 / 50 / 1.2 / 4 / 98, 158, 167
Actitis macularia / 0.078 / -0.485 / 6.10 / 0 / 100 / 47.1 / 2 / 58, 128
Agelaius phoeniceus / 1.000 / 3.146 / 0.31 / 90 / 0 / 5 / 43.6 / 4 / 10, 93, 128, 132
Aimophila carpalis / 0.013 / -0.615 / 1.05 / 0 / 0 / 31.0 / 4 / 20, 42, 132
Aix sponsa / 0.356 / 0.864 / 0.71 / 0.1 / 0 / 33.1 / 1 / 33, 84, 132
Alectoris rufa / 0.091 / -0.467 / 0.56 / 0.1 / 30 / 45.0 / 1 / 15, 128
Amphispiza bilineata / 0.202 / -0.345 / 0.05 / 0 / 0 / 31.5 / 4 / 20, 132, 172
Anas platyrhynchos / 0.530 / 1.295 / 1.31 / 0 / 0 / 50.0 / 1 / 50, 125, 128, 166, 184
Anser indicus / 0.159 / -0.388 / 0.20 / 0 / 0 / 48.7 / 1 / 33, 44
Aphelocoma californica / 0.062 / -0.509 / 0.05 / 0 / 0 / 50 / 35.0 / 3 / 108, 132, 173
Aphelocoma coerulescens / 0.000 / -0.702 / 0.11 / 0.1 / 0 / 60 / 27.6 / 3 / 108, 132, 147, 148
Aphelocoma ultramarina / 0.000 / -0.702 / 0.05 / 0 / 0 / 50 / 35.0 / 3 / 108, 132, 173
Aptenodytes forsteri / 0.168 / -0.379 / 0.20 / 0 / 100 / 50 / 66.4 / 73, 1988, 33
Aptenodytes patagonicus / 0.167 / -0.380 / 0.07 / 0 / 50 / 50 / 46.3 / 26, 33, 94, 110
Apteryx australis / 0.000 / -0.702 / 0.38 / 0 / 100 / 35.3 / 1 / 28, 33
Atlapetes pallidinucha / 0.253 / -0.298 / 0.0 / 4 / 68, 138
Aythya affinis / 0.635 / 1.557 / 0.72 / 0 / 0 / 54.0 / 1 / 33, 132, 184
Branta bernicla bernicla / 0.890 / 0.242 / 0.34 / 0 / 0 / 53.2 / 1 / 33, 131, 132
Branta canadensis / 0.312 / -0.248 / 0.20 / 0 / 0 / 38.3 / 1 / 1, 33, 132
Calcarius lapponicus / 0.397 / 0.415 / 0.04 / 17 / 0 / 55 / 68.4 / 4 / 4, 91, 128, 132
Calidris mauri / 0.212 / -0.336 / 0 / 50 / 38.4 / 2 / 121, 128
Calidris melanotos / 0.350 / 0.357 / 3.98 / 100 / 0 / 71.3 / 2 / 35, 132, 165
Calidris pusilla / 0.169 / -0.378 / 2.73 / 0 / 50 / 64.8 / 2 / 71, 128, 165
Campylorhynchus brunneicapillus / 0.216 / -0.332 / 0.10 / 0 / 0 / 50 / 31.5 / 4 / 39, 172
Carduelis flammea / 0.029 / -0.571 / 0.1 / 0 / 68.1 / 4 / 90, 128
Carpodacus mexicanus / 0.000 / -0.702 / 0.09 / 3 / 0 / 30 / 34.5 / 4 / 11, 27, 79, 132
Catamenia inornata / 0.000 / -0.702 / 0.0 / 4 / 68, 87
Centropus grillii / 1.000 / 0.501 / 0 / 100 / 97 / 8.4 / 67, 68 , 69, 159
Ceryle rudis / 0.388 / -0.187 / 0.17 / 0 / 60 / 60 / 0.0 / 128, 137
Cettia diphone / 0.000 / -0.702 / 0.10 / 75 / 0 / 0 / 37.5 / 4 / 6, 176, 190
Chionis minor / 0.000 / -0.702 / 0.12 / 0 / 0 / 50 / 46.5 / 2 / 18, 35
Chlamydotis macqueenii / 0.221 / -0.327 / 1.62 / 100 / 0 / 21.2 / 128, 145
Chlamydotis undulata / 0.165 / -0.382 / 0.98 / 100 / 0 / 21.2 / 128, 145
Ciconia ciconia / 0.000 / -0.702 / 0.30 / 0 / 46.0 / 76, 128
Colinus virginianus texanus / 0.311 / -0.249 / 86 / 28 / 30.0 / 1 / 19, 33, 132, 174
Corvus frugilegus / 1.000 / 0.501 / 0.70 / 0.1 / 0 / 69 / 47.4 / 3 / 101, 127, 128
Cyanopica cyanus / 0.384 / -0.190 / 0.22 / 0 / 0 / 39.0 / 3 / 31, 128
Cyphorhinus phaeocephalus / 0.000 / -0.702 / 0.20 / 0 / 0 / 9.0 / 4 / 39, 139, 177, 178
Diglossa humeralis / 1.000 / 0.501 / 0.0 / 4 / 68, 92
Diomedea chrysostoma / 0.000 / -0.702 / 0.07 / 0 / 50 / 50 / 54.0 / 33, 82
Diomedea exulans / 0.000 / -0.702 / 0 / 50 / 50 / 54.0 / 33, 83
Diomedea melanophris / 0.005 / -0.648 / 0 / 50 / 50 / 54.0 / 33, 82
Dromaius novaehollandiae / 0.088 / -0.471 / 0.09 / 7 / 100 / 32.0 / 1 / 13, 33, 109
Eudocimus albus / 0.000 / -0.702 / 0.30 / 0 / 55 / 57 / 28.0 / 33, 81, 132
Eudyptes chrysolophus / 0.333 / -0.231 / 1.15 / 0 / 50 / 50 / 54.0 / 33, 181
Euplectes orix nigrifrons / 0.540 / 1.320 / 1.70 / 0 / 0 / 8.0 / 4 / 64, 68, 159
Falco sparverius / 0.181 / -0.121 / 0.30 / 0 / 13 / 50 / 45.3 / 34, 132, 136
Falco tinnunculus / 0.139 / -0.409 / 0.46 / 0.1 / 0 / 90 / 53.2 / 114, 128
Ficedula hypoleuca / 0.447 / 1.092 / 1.75 / 16 / 0 / 44 / 57.4 / 4 / 128, 154, 155
Fregata magnificens / 1.000 / 2.092 / 0 / 50 / 14 / 12.8 / 25, 124, 128
Gallirallus philippensis / 0.319 / -0.242 / 0.08 / 0 / 23.3 / 35, 179
Geospiza fuliginosa / 1.000 / 3.146 / 0.0 / 4 / 68, 77
Gymnopithys leucaspis / 0.308 / -0.251 / 0.20 / 0 / 25 / 56 / 9.0 / 37, 177, 178
Gymnorhina tibicen dorsalis / 0.905 / 0.261 / 0.14 / 0 / 0 / 31.5 / 3 / 89, 146, 157
Hemignathus virens / 0.021 / -0.346 / 0 / 0 / 27 / 20.0 / 4 / 68, 132, 133
Himatione sanguinea / 0.000 / -0.702 / 0 / 0 / 26 / 20.0 / 4 / 68, 132, 133
Hirundo rustica / 0.283 / -0.272 / 0.90 / 0.1 / 0 / 47 / 57.1 / 4 / 115, 128, 144
Hylophylax naevioides / 0.459 / -0.132 / 0.20 / 0 / 50 / 50 / 9.0 / 37, 80, 177
Junco hyemalis / 0.163 / 0.316 / 0.90 / 0.1 / 0 / 56 / 37.2 / 4 / 23, 96, 115, 128, 132, 135
Lamprotornis chalybaeus / 1.000 / 0.501 / 0.20 / 0 / 0.2 / 4 / 46, 47, 55
Lamprotornis purpuropterus / 1.000 / 0.501 / 0.45 / 0 / 0.2 / 4 / 46, 47, 55
Laniarius funebris / 1.000 / 3.146 / 0 / 54 / 2.0 / 3 / 78, 149, 164
Lanius collaris / 0.401 / -0.177 / 0.40 / 0 / 0 / 0.2 / 3 / 48, 78
Lanius collurio / 0.109 / 0.122 / 0.26 / 0 / 0 / 56 / 45.3 / 3 / 62, 128
Larus occidentalis / 0.000 / -0.702 / 1.26 / 0 / 42 / 57 / 33.3 / 2 / 35, 84, 184, 185
Larus ridibundus / 0.214 / -0.334 / 4.66 / 0 / 50 / 53.1 / 2 / 72, 128
Lichenostomus penicillatus / 0.004 / -0.654 / <0.01 / 0 / 31.0 / 3 / 5, 86
Loxia leucoptera / 0.000 / -0.702 / 0.01 / 0 / 64.5 / 4 / 41, 128
Luscinia svecica / 0.082 / -0.370 / 0.25 / 5 / 0 / 40 / 47.2 / 4 / 65, 79, 128, 151
Malurus cyaneus / 0.514 / 1.256 / 0.84 / 0 / 0 / 50 / 35.2 / 3 / 129, 143
Manacus vitellinus / 0.189 / 0.400 / 100 / 0 / 0 / 9.0 / 24, 38, 177, 178
Manorina melanophrys / 0.014 / -0.611 / 0 / 37.0 / 3 / 86, 130
Megadyptes antipodes / 0.139 / -0.409 / 0.13 / 0 / 50 / 50 / 45.5 / 29, 33
Meleagris gallopavo / 1.000 / 3.146 / 0.33 / 100 / 0 / 33.0 / 1 / 33, 102, 132
Melospiza melodia / 0.000 / -0.702 / 0.11 / 3 / 0 / 71 / 45.5 / 4 / 20, 132, 162, 187, 188
Mimus polyglottos / 0.000 / -0.702 / 0.07 / 0.08 / 0 / 48 / 36.0 / 4 / 16, 39, 40, 103, 104, 115
Molothrus ater / 0.523 / 1.278 / 0.10 / 0 / 0 / 42.0 / 4 / 51, 52, 53, 128, 132
Myrmeciza longipes / 0.435 / 1.062 / 0.31 / 0 / 50 / 50 / 9.7 / 37, 56, 57
Nesomimus parvulus / 0.104 / -0.451 / 3.88 / 0 / 37 / 0.0 / 4 / 30, 39, 68, 70, 170
Pachycephala rufiventris / 0.215 / -0.333 / 0 / 36 / 50 / 33.2 / 3 / 113, 157
Parabuteo unicinctus / 1.000 / 0.501 / 0.02 / 0.1 / 30 / 50 / 32.2 / 34, 112, 172
Parus caeruleus / 0.122 / -0.429 / 0.11 / 17 / 0 / 55 / 45.2 / 4 / 22, 61, 115, 128
Parus major / 0.292 / -0.265 / 0.10 / 0.07 / 40 / 50 / 57.4 / 4 / 43, 128, 140, 142, 153
Parus montanus / 0.285 / -0.271 / 0.18 / 0 / 0 / 57 / 57.5 / 4 / 115, 128, 156
Passer domesticus / 0.103 / 0.098 / 0.31 / 10 / 39 / 45 / 42.0 / 4 / 85, 115, 128
Passer motitensis rufocinctus / 0.027 / -0.576 / 0.20 / 0 / 0.2 / 4 / 27, 45, 47
Perdix perdix / 0.000 / -0.702 / 0.03 / 0 / 0 / 45.1 / 1 / 8, 63, 106, 128, 152
Petrochelidon pyrrhonota / 0.241 / -0.309 / 0.01 / 0 / 50 / 50 / 41.1 / 4 / 38, 132, 163
Phaeton rubricauda / 0.018 / -0.599 / 0.11 / 0 / 50 / 50 / 22.2 / 33, 105
Phalacrocorax capensis / 1.000 / 0.501 / 0.02 / 0 / 50 / 50 / 22.4 / 12, 33
Phalaropus fulicarius / 0.043 / -0.715 / 6.00 / 0 / 100 / 20.7 / 2 / 35, 60, 128
Phalaropus lobatus / 0.088 / -0.596 / 1.95 / 0 / 100 / 58.2 / 2 / 35, 71, 128
Phalaropus tricolor / 0.029 / -0.967 / 3.61 / 0 / 100 / 58.2 / 2 / 35, 59, 60, 122, 123, 128
Picoides borealis / 0.300 / -0.258 / 0.16 / 0 / 30 / 37 / 35.3 / 97, 128
Picoides pubescens / 0.202 / -0.345 / 2.23 / 0 / 50 / 50 / 40.3 / 36, 95, 132
Pipilo erythropthalmus / 0.545 / 1.332 / 0.16 / 0.1 / 0 / 42 / 44.6 / 4 / 17, 20, 161, 132
Plectrophenax nivalis / 0.000 / -0.702 / 0.17 / 0.1 / 0 / 50 / 71.1 / 4 / 128, 132, 141
Plocepasser mahali / 0.077 / -0.487 / 0.04 / 0 / 25 / 50 / 13.0 / 4 / 100, 159, 189
Ploceus baglafecht reichenowi / 0.195 / -0.629 / 0.80 / 0 / 50 / 22.3 / 4 / 45, 193
Ploceus philippinus / 0.199 / 0.430 / 1.50 / 0 / 0.2 / 4 / 107, 120, 134
Pooecetes gramineus / 0.000 / -0.702 / 0.10 / 0.1 / 35 / 46.0 / 4 / 20, 132, 185
Psittacula krameri / 0.044 / -0.540 / 0 / 50 / 22.3 / 99, 128
Ptilonorhynchus violaceus / 1.000 / 3.146 / 100 / 0 / 0 / 28.0 / 3 / 14, 38, 157
Pygoscelis adeliae / 0.310 / -0.250 / 0.11 / 0 / 63 / 50 / 65.4 / 33, 73, 175
Pygoscelis papua / 0.215 / -0.333 / 0.11 / 0 / 50 / 50 / 50.1 / 33, 111, 181
Saxicola torquata / 0.309 / 0.742 / 0.07 / 0.1 / 0 / 50 / 38.7 / 4 / 21, 47, 74, 128
Somateria mollissima / 0.416 / 1.015 / 1.31 / 0.1 / 0 / 58.2 / 1 / 66, 128
Spizella arborea / 0.012 / -0.618 / 0 / 0 / 50 / 68.4 / 4 / 20, 90, 132
Streptopelia decaocto / 0.000 / -0.702 / 0.27 / 0 / 33 / 50 / 48.7 / 126, 128
Sturnella neglecta / 0.177 / -0.370 / 0.10 / 53 / 0 / 45.0 / 4 / 108, 132, 186
Sturnus vulgaris / 1.000 / 0.501 / 0.19 / 29 / 24 / 50 / 46.6 / 4 / 7, 32, 128
Sula capensis / 0.000 / -0.702 / 0 / 50 / 50 / 32.0 / 33, 75
Sula dactylatra / 0.000 / -0.702 / 0.01 / 0 / 50 / 50 / 15.3 / 33, 105
Sula nebouxii / 0.185 / -0.362 / 0 / 50 / 50 / 21.5 / 33, 191
Sula sula / 0.000 / -0.702 / 0.01 / 0 / 50 / 50 / 22.2 / 33, 105
Tadorna ferruginea / 0.014 / -0.412 / 3.65 / 0 / 0 / 43.9 / 1 / 128, 171
Tetrao tetrix / 1.000 / 3.146 / 1.15 / 100 / 0 / 65.0 / 1 / 2, 128
Tetrao urogallus / 1.000 / 3.146 / 0.20 / 100 / 0 / 67.0 / 1 / 88, 128
Thraupis episcopus / 0.000 / -0.702 / 0.20 / 0 / 9.0 / 4 / 92, 160, 177, 178
Threskiornis melanocephalus / 0.000 / -0.702 / <0.01 / 0 / 41.8 / 33, 192
Thryothorus nigricapillus / 0.391 / 0.155 / 0.20 / 0 / 9.0 / 4 / 39, 177
Toxostoma curvirostre / 0.000 / -0.702 / 0.11 / 0 / 75 / 50 / 31.5 / 4 / 39, 172
Turdus fuscater / 0.000 / -0.702 / 0.0 / 4 / 39, 68
Turdus grayi / 0.000 / -0.702 / 0.20 / 0 / 9.0 / 4 / 39, 115, 177, 178
Turdus merula / 1.000 / 3.146 / 0.04 / 0.1 / 0 / 51 / 47.5 / 4 / 128, 150
Vestiaria coccinea / 0.000 / -0.702 / 0 / 0 / 29 / 20.0 / 4 / 68, 132, 133
Vireo olivaceus / 0.036 / -0.556 / 0.45 / 0 / 0 / 41 / 39.2 / 3 / 128, 132, 169
Vireo solitarius / 0.000 / -0.702 / <0.01 / 0 / 49 / 52 / 37.7 / 3 / 119, 132, 168, 169
Xanthocephalus xanthocephalus / 0.444 / 1.084 / 0.90 / 96 / 0 / 7 / 47.1 / 4 / 9, 54, 132, 182
Zonotrichia albicollis / 0.077 / -0.487 / 0.38 / 0.1 / 0 / 45 / 35.6 / 4 / 3, 20, 115, 132, 180
Zonotrichia capensis / 0.149 / -0.399 / 0 / 0 / 0.2 / 4 / 20, 117, 118, 118
Zonotrichia leucophrys / 0.076 / -0.488 / 0.15 / 7 / 0 / 40 / 52.4 / 4 / 20, 116, 117, 132, 188, 184

1 Melanization is the proportion of black to all frontal breeding plumage (i.e. head and breast).

2 Melanin dichromatism is the residuals from the linear regression of male – female melanization.

2 Circulating T levels at molt are approximated by non-breeding baseline T for species with a single post-breeding molt, and by peak pre-breeding T for species with a second, pre-breeding molt.

4 Taxa: (1) basal lineage, (2) Charadriiformes, (3) Corvida, (4) Passeroidea.

5 Data sources:

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