Table S1.
Cellular composition of the brains of 28 bird species
| Species | n | Body mass, g | Brain mass, g | Total neurons, ×106 | Total nonneurons, ×106 |
| Parrots | |||||
| Green-rumped parrotlet | 3 | 23.2 ± 0.7 | 1.146 ± 0.042 | 227.20 ± 3.81 | 135.00 ± 4.70 |
| Budgerigar | 3 | 35.3 ± 4.6 | 1.317 ± 0.041 | 321.82 ± 10.62 | 176.05 ± 4.26 |
| Cockatiel | 3 | 101.0 ± 4.6 | 2.205 ± 0.132 | 452.77 ± 44.51 | 234.66 ± 10.25 |
| Eastern rosella | 3 | 102.0 ± 3.4 | 2.716 ± 0.032 | 641.88 ± 79.00 | 318.17 ± 47.28 |
| Monk parakeet | 3 | 94.0 ± 1.7 | 3.420 ± 0.168 | 696.77 ± 75.26 | 393.49 ± 21.06 |
| Alexandrine parakeet | 3 | 223.0 ± 5.3 | 5.699 ± 0.492 | 1,096.26 ± 89.81 | 572.74 ± 28.11 |
| Goffin's cockatoo | 2 | 244.8 ± 3.5 | 8.275 ± 0.548 | 1,160.59 ± 101.87 | 792.22 ± 39.88 |
| Gray parrot | 2 | 453.5 ± 47.4 | 8.827 ± 0.859 | 1,565.93 ± 128.99 | 880.59 ± 2.06 |
| Sulfur-crested cockatoo | 1 | 430.0 | 10.131 | 2,121.93 | 1,001.81 |
| Kea | 1 | 708.0 | 13.593 | 2,148.67 | 975.57 |
| Blue and yellow macaw | 1 | 1,008.0 | 20.731 | 3,135.79 | 1,800.03 |
| Variation, max./min. | 43.3× | 18.1× | 13.8× | 13.3× | |
| Songbirds | |||||
| Goldcrest | 3 | 4.5 ± 0.1 | 0.357 ± 0.022 | 163.87 ± 8.67 | 44.16 ± 6.57 |
| Zebra finch | 3 | 17.4 ± 2.1 | 0.494 ± 0.040 | 135.98 ± 6.82 | 59.75 ± 2.03 |
| Blackcap | 3 | 16.6 ± 1.3 | 0.774 ± 0.037 | 156.73 ± 18.91 | 86.28 ± 9.18 |
| Great tit | 3 | 17.1 ± 0.3 | 0.940 ± 0.066 | 225.98 ± 46.97 | 115.43 ± 23.43 |
| Starling | 3 | 73.1 ± 1.9 | 1.855 ± 0.047 | 482.50 ± 88.29 | 215.64 ± 13.49 |
| Blackbird | 3 | 85.0 ± 7.5 | 1.887 ± 0.117 | 379.41 ± 43.33 | 222.57 ± 27.48 |
| Azure-winged magpie | 2 | 84.1 ± 16.0 | 3.393 ± 0.486 | 740.59 ± 0.35 | 349.49 ± 33.17 |
| Hill mynah | 2 | 262.1 ± 30.7 | 3.670 ± 0.362 | 906.13 ± 45.38 | 380.79 ± 3.56 |
| Eurasian jay | 3 | 160.0 ± 12.5 | 4.597 ± 0.307 | 1,085.42 ± 159.56 | 484.42 ± 32.87 |
| Magpie | 3 | 178.6 ± 11.5 | 5.425 ± 0.617 | 897.27 ± 57.43 | 535.97 ± 15.96 |
| Jackdaw | 3 | 209.7 ± 25.1 | 6.023 ± 0.305 | 967.99 ± 106.66 | 565.92 ± 37.87 |
| Rook | 3 | 429.3 ± 35.6 | 8.357 ± 0.312 | 1,508.72 ± 38.25 | 855.55 ± 92.10 |
| Raven | 3 | 1,070.7 ± 73.2 | 14.135 ± 0.558 | 2,170.68 ± 72.67 | 1,242.85 ± 98.19 |
| Variation, max./min. | 237.9× | 39.6× | 16× | 28.1× | |
| Other birds | |||||
| Rock pigeon | 3 | 322.5 ± 22.7 | 2.095 ± 0.123 | 309.96 ± 33.33 | 262.18 ± 18.94 |
| Red junglefowl | 3 | 861.3 ± 107.3 | 2.819 ± 0.200 | 220.84 ± 44.50 | 286.68 ± 17.35 |
| Barn owl | 3 | 369.7 ± 37.7 | 5.618 ± 0.404 | 689.54 ± 39.64 | 522.49 ± 25.29 |
| Emu | 2 | 32,600.0 ± 1,414.2 | 21.811 ± 2.037 | 1,335.40 ± 29.01 | 1,528.66 ± 118.97 |
Species ordered by increasing brain size. All values are given as mean ± SD; n, number of individuals analyzed.