Fig 1.
Map of the migration grounds for S. Citrina.
Breeding takes place through June-July while nonbreeding takes place December-February. Migration takes place in Aug-Oct and Mar-May [16]. Square indicates the location of sample collection in Houston, Texas.
Fig 2.
Primary [P] and secondary [S] flight feathers are shown in red and blue respectively, along the right [RR] and left [RL] rectrices in green. The primary coverts [PC] are in yellow, the median coverts [MC] are in brown, and the greater coverts [GC] are in pink. The dorsal body feathers are also shown, with rump feathers shown in purple, back in orange, and throat in teal.
Fig 3.
Comparison of the feather δ13C, δ15N, δ18O, and δD values between the 2017 and 2018 samples.
Statistical differences between the samples are shown in Table 1. The 2017 sample values are shown in blue, crossed circles while the 2018 samples are shown in red, full circles. Arrows below the x-axis show the proposed molt strategy from earliest feather molted to last feather molted for each section [13].
Table 1.
Correlation coefficients (R2) for feather isotopic compositions involved in several proposed molt patterns.
Fig 4.
Comparison of the δ18O vs. δD for the 2017 and 2018 feather sets and local meteoric waterlines.
The meteoric water lines included are the contiguous United States (solid, green), Southeastern United States (dotted, orange), Northeastern United States (short dash, black), and Central America (long dash, purple) [29, 35].