Organising a juvenile ratio monitoring programme for 10 key waterbird species in the Yangtze River floodplain: analysis and proposals

Table 1 The overall annual juvenile ratio (expressed as proportion of first winter birds out of all birds aged) among 10 large-bodied waterbird species sampled in the Yangtze River Floodplain from 2016 to 2019

Species	2016	2017	2018	2019	Mean ± SD
Common Crane	0.187	0.135	0.184	0.241	0.187 ± 0.037
Siberian Crane	0.178	0.039	0.146	0.173	0.134 ± 0.056
Hooded Crane	0.257	0.169	0.231	0.252	0.227 ± 0.035
White-naped Crane	0.146	0.125	0.188	0.253	0.178 ± 0.049
Swan Goose	0.133	0.096	0.108	0.175	0.128 ± 0.030
Lesser White-fronted Goose	0.344	0.060	0.090	0.113	0.152 ± 0.112
Greater White-fronted Goose	0.164	0.122	0.138	0.187	0.153 ± 0.025
Greylag Goose	0.259	0.104	0.165	0.222	0.188 ± 0.059
Bean Goose	0.184	0.104	0.153	0.137	0.145 ± 0.029
Bewick’s Swan	0.241	0.125	0.198	0.251	0.204 ± 0.050

The values in bold represent the lowest juvenile ratio from all 4 years for each species, which for all species fell in 2017

ISSN: 2053-7166