Between September 2025 and January 2026, wildlife agencies logged 241 wild bird mortality events across 28 states — more than 126,000 dead birds, reported through the U.S. Geological Survey’s National Wildlife Health Center. Highly pathogenic avian influenza, H5N1, was confirmed or suspected in 123 of those events. Just over half.

We’ve covered rattlesnakes, coyotes, moose, leptospirosis, and blue-green algae on this site. We haven’t covered bird flu. That gap needed closing, because the exact place H5N1 concentrates — lakeshores, wetland edges, open fields where geese and ducks gather — is exactly where off-leash trail dogs go to sniff, splash, and occasionally eat something they shouldn’t.

This isn’t a panic post. Dog illness from H5N1 remains rare worldwide. But “rare” isn’t “never,” and the exposure pathway is specific enough that it’s worth understanding before your dog finds a dead goose on the trail.

Quick Verdict: H5N1 Risk for Trail Dogs

Factor	What You Need to Know
Current outbreak scale	241 wild bird die-off events, 28 states, Sept 2025–Jan 2026 (NWHC)
H5N1 involvement	Confirmed or suspected in 123 of those events
Dog susceptibility	Dogs can contract H5N1, but documented illness is exceptionally rare
Highest-risk behavior	Eating or mouthing a dead or sick wild bird
Lowest-risk behavior	Normal leashed hiking with no bird contact
Where risk concentrates	Lakeshores, wetland margins, fields near migratory flocks
Best prevention	Leash near water, block carcass access, skip raw poultry diets

Bottom line: Your dog isn’t at high risk from breathing the same air as sick birds. The risk is scavenging — and that’s a behavior you can actually control.

What’s Actually Happening With This Outbreak

H5N1 isn’t new. This particular lineage re-emerged in North America in late 2021 and has hit wild birds every year since — this is the fourth consecutive season. What’s notable about the September 2025 through January 2026 window is the scale and spread: all four major migratory flyways (Atlantic, Central, Mississippi, and Pacific) reported die-offs, and the single largest event on record in the tracking system involved roughly 67,200 geese at a Kansas wildlife refuge over just a few months.

Wildlife agencies track these events through WHISPers, the Wildlife Health Information Sharing Partnership event reporting system, which is how the NWHC compiles nationwide numbers instead of relying on scattered local reports. That’s useful context: this isn’t an isolated regional die-off, it’s a season with unusually broad geographic spread, and it lines up with fall and winter waterfowl migration — the exact time and place your dog is most likely to encounter a sick or dead bird on a shoreline.

Can Dogs Actually Get H5N1?

Yes, but it’s uncommon, and the cases that exist follow a clear pattern. According to the CDC, avian influenza has been documented in dogs going back to a 2004 case in Thailand, where a dog died after eating a duck carcass during an active outbreak. Since then, a handful of additional cases have surfaced in the UK and Canada, all tied to dogs eating infected birds or carcasses. Compare that to cats, which the American Veterinary Medical Association has flagged as considerably more vulnerable, with documented deaths linked to raw pet food and unpasteurized milk in the current outbreak.

Dogs are built differently for this virus. Their respiratory tract doesn’t bind the H5N1 virus as readily as a cat’s does, which is likely why — even with millions of dogs living alongside active outbreaks for four years running — confirmed clinical illness in dogs stays exceptionally rare. When it does happen, it’s almost always tied to one specific behavior: eating a dead or dying bird.

That’s the number that matters here. Not “dogs can get bird flu” in the abstract, but “dogs that eat infected carcasses can get bird flu.” Everything else — walking near a lake, smelling bird droppings, being in the same field as a flock — carries meaningfully lower risk.

What Puts a Trail Dog at Risk

Think about where you actually let your dog off-leash. Lakeshores. Riverbanks. Open meadows near wetlands. Farm field edges. These are the same places waterfowl and shorebirds concentrate — and the same places a sick bird, unable to fly well, ends up stranded and easy for a curious dog to find.

High-risk scenarios:

• Your dog finds and eats (or mouths and doesn’t fully swallow) a dead or visibly sick wild bird
• Your dog rolls in or licks bird droppings concentrated near a die-off site
• Your dog investigates a carcass pile near a lakeshore, wetland, or field
• You feed a raw poultry diet during an active regional outbreak

Lower-risk scenarios:

• Leashed hiking through areas with wild bird activity but no carcass contact
• Swimming in water without direct contact with sick or dead birds
• Passing by (not engaging with) waterfowl on a trail

This is the same logic that applies to leptospirosis and blue-green algae — both hazards concentrated at exactly the water’s edge your dog wants to explore. If you already carry a mental checklist for lakeshore hazards, bird flu slots right in next to them, not above them.

What Should You Do If Your Dog Eats or Mouths a Dead Bird?

1. Get the bird away from your dog immediately. Don’t let your dog carry, chew, or continue investigating the carcass. Use a leash, a “drop it” command, or physically redirect if needed.
2. Don’t handle the bird bare-handed. If you need to move it off-trail, use a bag or gloves and wash your hands thoroughly afterward.
3. Rinse your dog’s mouth and face with clean water if there was direct contact with the carcass.
4. Note the location and report it. Many states have wildlife mortality reporting hotlines or online forms — a cluster of dead birds is exactly the kind of thing agencies want to know about.
5. Call your vet, especially if your dog swallowed tissue from the bird. Describe what happened and where. Your vet can advise on monitoring or testing based on local outbreak activity.
6. Watch for symptoms over the following days. Lethargy, loss of appetite, fever, respiratory distress (coughing, labored breathing, nasal or eye discharge), or neurological signs like tremors or incoordination. If any of these show up, get to a vet promptly and mention the bird exposure specifically.

CDC and AVMA Guidance for Pet Owners

The prevention advice here isn’t complicated, and most of it overlaps with things careful trail owners already do. The CDC’s pet guidance and AVMA both point to the same core practices:

• Keep dogs leashed near water and shorelines, especially in areas with known die-off activity or dense waterfowl populations. A leash is the single most effective control you have — it stops the scavenging behavior before it starts.
• Prevent contact with wild birds, backyard poultry, and carcasses. That includes not letting your dog investigate dead birds “just to sniff.” A sniff can turn into a mouth grab faster than you can call your dog off.
• Skip raw meat and raw poultry diets during active outbreak periods. This is more of a cat issue — raw diets have been linked to severe illness and death in cats — but the AVMA recommends the same caution for dogs, since raw poultry products can carry the virus even after a bird has died.
• Avoid unpasteurized milk products for pets, for the same underlying reason.

None of this requires staying off trails. It requires the same situational awareness you’d already use for a rattlesnake sighting or a coyote encounter near a den — know what’s happening in your area, and adjust your dog’s off-leash freedom accordingly.

How to Know If There’s a Die-Off Near You

Before a hike near lakes, wetlands, or agricultural fields, it’s worth a quick check for local activity. Most state wildlife or agriculture departments post updates when they’re tracking a die-off event, and local news tends to cover unusual numbers of dead birds fast — dead swans on a popular lake get attention. If you see multiple dead or obviously sick birds in one area (staggering, unable to fly, head tremors), that’s your signal to leash up, keep your dog well back, and route around the area entirely rather than push through.

This is worth building into the same seasonal-awareness habit you’d use for coyote denning season or giardia risk at creek crossings — a five-minute check before you go, adjusted to what’s actually active in your area right now.

The Bigger Picture: Rare Risk, Real Precaution

Here’s the tension worth sitting with. Four consecutive years of H5N1 circulating in North American wild birds, hundreds of documented die-off events, well over a hundred thousand dead birds in a single five-month window — and still only a small handful of confirmed dog cases worldwide, nearly all tied to eating an infected carcass. Dogs are not the vulnerable species here. Cats and, in specific occupational contexts, humans carry more documented risk.

That’s not a reason to ignore it. It’s a reason to be precise about what actually matters: don’t let your dog eat dead birds, don’t feed raw poultry during active outbreaks, and leash up near water when local die-off activity is elevated. That’s a short list, and most of it is stuff a careful trail owner is already halfway doing.

If your dog’s off-leash trail time has been unrestricted around lakes and wetlands, this is a reasonable season to tighten that up — not out of fear, but because a leash costs you nothing and closes off the one exposure pathway that actually matters. Pack the basics you’d already carry for a trail emergency, keep your dog close near the shoreline, and let the geese have their space this season.

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Statistics on wild bird mortality events sourced from the USGS National Wildlife Health Center, current as of the September 2025–January 2026 reporting period. Pet health guidance referenced from the CDC and AVMA. Outbreak conditions change; check current state wildlife agency reports for local die-off activity before heading out.