Table 1. Clade-specific frequency of melanin concentration gradients in feathers.

Order	Percentage of feathers with color gradient 1	Number of feathers sampled
Sphenisciformes	100.0	10
Anseriformes	88.0	25
Gaviiformes	87.5	8
Charadriiformes	69.2	13
Podicipediformes	68.8	16
Falconiformes	66.7	6
Suliformes	57.1	21
Procellariiformes	50.0	10
“core-Gruiformes”	47.8	23
Ciconiiformes	35.7	14
Accipitriformes	29.6	27
Coraciiformes	25.0	16
Apodiformes	24.0	25
Columbiformes	19.0	21
Cuculiformes	11.1	18
Passeriformes	7.8	51
Tinamiformes	0.0	7
Piciformes	0.0	10

Names in bold denote clades of birds with largely aquatic ecologies.