BioOne Ambassador Award

The first House Finch (Haemorhous mexicanus) I held in San Luis Potosi, Mexico amazed me. Small, light, and full of life, with that bright red head, bright like the tiny drop of blood I collected. I released him but his secret stayed hidden in my hands, silent inside that drop.

All of the finches we sampled looked active, energetic, even happy, but examining the tiny drops of blood told a different story. The birds were fighting invisible wars with Mycoplasma gallisepticum, a bacterium that originally affected only poultry but is now found in wild birds in the United States, and haemosporidia, blood parasites related to avian malaria. Either infection alone challenges a bird’s immune system. But when both attack together — a co-infection — the impact on the bird is amplified.

In a collaborative effort between Cornell University and multiple Mexican academic institutions, the research aimed to identify the presence of these microbes in wild House Finches in Mexico and understand their effect on the bird. We sampled wild finches across 12 states in Mexico, and what we found alarmed us: 74% were infected with the poultry bacterium, and 43% carried the malaria-related parasites. Many were battling both at once, and yet showed no signs of illness.

So, what were these microbes doing behind the scenes while the birds still looked healthy, their feathers smooth, their eyes clear and open, not swollen or crusted as in visibly sick birds?