Why Birds Chase and Fight in the Fall: Survival of the Fittest

In the past couple of weeks, I’ve noticed a flurry of bird activity that goes beyond the usual squabbles. Birds have been chasing and fighting each other like never before. The most dramatic incident was a pair of Carolina Wrens that got into a fierce, knock-down drag-out fight right on the ground. It lasted for over a minute, and it was intense! While I see birds getting into little disagreements at the feeders all year long, something about the fall seems to bring out more aggressive behavior. Curious about why this happens, I dug into the reasons behind these seasonal bird battles.

Here’s what I found:

Competition for Food

As we head into the colder months, food becomes harder to find, and this scarcity ramps up competition. Birds know that winter is coming, and they’re working hard to stock up on calories. Some of the behaviors I’ve seen, like chasing others away from feeders or even stealing food, make more sense when you realize just how crucial it is for them to build up energy reserves.

• Birds aggressively defend feeders and natural food sources.
• Some species, like crows and gulls, are especially prone to these squabbles as their food is already limited.

Territorial Defense

Even though the breeding season is over, many birds still hold tight to their territories. This can be because they want to protect food sources for the winter or even secure prime spots for the next breeding season. I’ve seen birds chase intruders off the feeders, but they’re not just guarding food—they’re reinforcing their dominance in the area.

• Birds defend territories to ensure they have enough food and shelter.
• This behavior helps maintain a hierarchy within their species.

Migratory Pressures

Fall migration means that more birds are moving through different areas, and these newcomers can cause tension. I’ve noticed increased activity around my feeders, and I suspect it’s partly due to migratory birds passing through.

• Resident birds will defend their space from migrants.
• Migrating birds may find themselves competing with locals for limited resources, adding to the tension.

Species-Specific Behaviors

Not all birds chase and fight for the same reasons. Some are more territorial, while others might be practicing their flying skills or establishing dominance. Take hummingbirds, for example—they’re notorious for chasing anything and everything away from their feeders, not just other hummingbirds.

• Same-species fights can help establish dominance.
• Inter-species fights often happen around feeders or prime feeding areas.

Hormonal Changes

While hormones mainly drive springtime aggression, some birds experience hormonal shifts in the fall that trigger territorial or competitive behaviors. It’s fascinating to think that some of these fall squabbles might be tied to an internal clock telling them to prepare for the months ahead.

Protecting Winter Resources

Birds are already thinking ahead to winter, and part of the fighting behavior could be tied to their need to protect important resources like food caches or sheltered spots.

• Birds will defend their winter roosting sites and food sources.
• Sheltered areas, crucial for staying warm, are fiercely protected.

Final Thoughts

Though it can be a bit surprising to see birds in such heated fights, these battles are a natural part of their survival strategy. For us wildlife photographers, these moments offer a glimpse into the fierce determination birds show as they prepare for the changing seasons. And let’s be honest, photographing dynamic bird behavior like this is a treat—fall has its own kind of wild energy, and it’s all happening right in front of us.

So, the next time you see birds chasing and fighting each other, just remember—they’re not being mean, they’re simply fighting for their survival.