There is nothing wrong at all with the segments of the article you quoted. The main premise presented in the article is that electrocuted birds are a plausible cause of wildfires, in addition to human activity (the article specifically reports that human activity is the primary cause of wildfires).

The authors' methodology to find online reports was valid. They used alerts to collect online published reports of electrocuted birds, and then manually checked each report to discard any that were speculative or lacked hard evidence. After this, the authors found 44 reports of electrocuted birds causing wildfires. At most, your strongest critique is that the methods could have been more comprehensive to find additional reports. That is technically correct, but it doesn't invalidate the main premise that wildfires caused by birds do happen, and are not one-off phenomena (via the 44 reports from the described method).

>"and then they quote a guy who "has studied" it in Spain but wasn't involved with this."

It is responsible and encouraged behavior to quote someone who wasn't involved with the study. This avoids bias where the only interviewed people are affiliated with the study, and are more likely to talk it up. Interviewing uninvolved experts in the field opens the door to possible critiques.

>"Then they quote two other studies from four years ago."

Four years isn't inherently long ago enough to be irrelevant. This is especially true when the premise is that electrocuted birds have been a significant cause of wildfires, not just one-off occurrences.