<p>Feeders filled with sugar solution are commonly used in cities to attract hummingbirds to homes and gardens. Some effects that the use of feeders can have on hummingbird and plant populations have been documented. However, the importance of feeders in the seasonal dynamics of floral resource use has so far remained unexplored. In this study we (1) we evaluated whether temperature and precipitation influence the frequency of hummingbird visits to plants; (2) determined whether the structure of the hummingbird-resource interaction network differs between the dry and rainy seasons; (3) determine the core resources of the network during the dry and rainy seasons; (4) and described the pattern of core resources use during the dry and rainy seasons in Mexico City. Our results indicate that the highest frequency of visits to feeders occurred during the transition between the dry and rainy seasons. Higher precipitation negatively influenced the proportion of visits hummingbirds made to floral resources. The structure of the hummingbird-resource interaction network presented a generalized structure with low levels of specialization, nestedness and modularity during both seasons. Finally, feeders were core resources in the interaction network during both seasons of the year (dry and rainy), and their importance increased during the rainy season. Our research provides evidence of the importance of feeders in the seasonal dynamics of hummingbirds’ floral resource use in Mexico City.</p>