Table 2. Statistical comparison of δ13C and δ15N between various tissues of individual herbivorous waterbirds.
Tissue | Isotope | Blood cells | Claw | Back feather | Primary feather | ||||
t | p | t | p | t | p | t | p | ||
Plasma | C | 8.74 | 0.001 | −1.79 | 0.10 | −3.52 | 0.003 | −3.84 | 0.001 |
N | 7.16 | 0.001 | 0.14 | 0.89 | −4.39 | 0.001 | −6.45 | 0.001 | |
Blood cells | C | −7.16 | 0.001 | −6.81 | 0.001 | −14.04 | 0.001 | ||
N | −10.11 | 0.001 | −10.20 | 0.001 | −20.57 | 0.001 | |||
Claw | C | −1.66 | 0.12 | −2.04 | 0.06 | ||||
N | −2.37 | 0.04 | −9.53 | 0.001 | |||||
Back feather | C | 0.84 | 0.41 | ||||||
N | −3.73 | 0.002 |
Tissues are blood plasma, blood cells, and keratinous tissues: claw, back feather and first primary feather from Bewick Swans (Cygnus columbianus bewickii, n = 9) and mallards (Anas platyrhynchos, n = 9). Data were pooled for paired t-tests.