Table 1.

Mean and 95% confidence interval (CI) for δD and δ¹³C values of monarch butterflies collected from 13 wintering colonies in Mexico

Wintering colony	δD, ‰	95% CI, ‰	n	δ13C, ‰	95% CI, ‰	n
Llano el Amparo	−104  ±  11	−107 to −100	47	−27.6  ±  1.1	−27.9 to −27.3	47
Altamirano	−104  ±  8	−106 to −101	45	−27.6  ±  1.1	−27.9 to −27.3	47
Sierra Chincua Barranca Hondon	−110  ±  10	−113 to −107	44	−27.5  ±  1.3	−27.9 to −27.2	47
Sierra Chincua Llano el Toro	−105  ±  8	−108 to −103	46	−27.3  ±  1.1	−27.7 to −27.0	48
Sierra Chincua Barranca la Meurto	−106  ±  11	−110 to −103	48	−27.4  ±  0.9	−27.7 to −27.2	50
Cerro Pelon La Gota de Agua	−110  ±  8	−112 to −107	45	−27.7  ±  1.3	−28.1 to −27.3	48
Cerro Pelon Los Cedrales	−107  ±  9	−109 to −104	45	−27.6  ±  1.4	−28.0 to −27.2	49
Herrada	−106  ±  10	−109 to −103	48	−27.5  ±  1.1	−27.8 to −27.2	48
Las Palomas	−104  ±  9	−107 to −101	48	−27.4  ±  1.1	−27.8 to −27.1	46
La Mesa	−104  ±  9	−107 to −102	49	−27.4  ±  1.3	−27.8 to −27.0	48
El Rosario El Campanario	−108  ±  11	−111 to −104	48	−27.7  ±  1.0	−28.0 to −27.4	50
El Rosario Planos de los Conecos	−106  ±  11	−110 to −103	44	−27.6  ±  1.2	−28.1 to −27.4	49
San Andres	−106  ±  10	−109 to −103	45	−27.7  ±  1.2	−28.1 to −27.4	50

Italicized sites refer to discrete subcolonies of monarchs that are generally considered part of the larger colony indicated.