When to Worry: Warning Signs in the First Weeks With a New Pet

The first two weeks are less about knowing what is wrong and more about knowing what "wrong" looks like at all. New animals hide illness — cats because they always have, dogs because they are still working out whether it is safe to show it, birds because in the wild it is the difference between a perch and a predator. Here is how to tell the difference between an animal that is settling in and one that needs a vet — and what "worth a call" looks like for each species.

Here is the short version. In the first weeks with any new pet, some of what you see will look worrying and will not be. Some of what you see will look fine and will not be. The single most useful skill in that period is knowing which class each thing belongs to. This article assumes you have already brought the animal home; if you are still deciding on a species, are you ready for a cat?, are you ready for a puppy?, and are you ready for a parrot? cover that side. Here we are dealing with the animal that is already in the house, and with the question every new owner asks in the first fortnight: is this normal?

Why new animals are hard to read

Every animal that arrives in your house is doing two things at once. It is adjusting to a completely new environment — new smells, new sounds, no familiar animals, unfamiliar routines — and it is also, quietly, being itself. Some of the itself is health; some of the itself is habit; some is trauma from before you got them. The problem is that many of the outward signs of "settling in" and the outward signs of "unwell" overlap almost perfectly.

A cat that hides for the first three days is settling in. A cat that hides for the first three days and stops using the litter box is something else. A puppy that skips one meal is settling in. A puppy that skips one meal and is lethargic on top of the tiredness of arrival is something else. A bird that sits fluffed on one perch is settling in. A bird that sits fluffed on one perch and does not straighten up when you enter the room is something else.

The pattern is always the same: it is not the symptom that matters as much as what is stacked on top of it, and how long it lasts. A single sign that resolves within a few hours is almost never worth a vet call. Two signs together, or one sign that persists past a threshold, almost always is.

That is the principle. The rest of this article is how it applies to cats, dogs, and birds specifically — because the thresholds and the specific signs are different for each.

The single most useful habit: baseline in the first three days

Before you can spot changes from the baseline, you need to have one. In the first three days, without doing anything active with the animal, note four things:

How much food and water it takes in a day — even roughly.
How often it uses the toilet, and what the output looks like.
How much time it spends sleeping, active, or watchful, and where.
Its resting posture — how it sits or stands when nothing is happening.

You do not need to write these down formally. You just need to have watched enough that on day seven, when something looks different, you notice. Owners who miss early illness usually miss it because they never had a baseline to compare against — they were looking at the animal for the first time on the day it stopped being well.

Cats: what is normal, and what to call about

Most of what alarms new cat owners in the first two weeks is ordinary:

Hiding for most of the day, especially the first three or four days.
Coming out only at night, or only when the household is quiet.
Skipping the first meal, and eating very little for the first 24 hours.
Startling at ordinary noises — doorbells, hoovers, dropped cutlery.
Not wanting to be touched yet, even by the person who fed them.
Sleeping 16 to 20 hours a day — this is a baseline for cats, not a warning sign.

What is worth a call:

No food or water at all by the end of day two.
No litter box use at all across 48 hours.
Laboured or open-mouthed breathing — cats do not pant in health, and open-mouthed breathing is an emergency.
Vomiting or diarrhoea that repeats, or contains blood.
Any discharge from eyes or nose that is thick, coloured, or continuous.
A third eyelid visible across the eye at rest — this is a classic sign of a cat that is unwell.
Visible weight loss (you can see it in a week if the cat is small and losing) or a coat that has gone rough and unkempt.
Any injury, obvious swelling, or the cat vocalising in a way you have not heard before, particularly when moving.

The Cornell Feline Health Center's advice on new arrivals holds regardless of symptoms: every new cat should be checked by a veterinarian as soon as possible after coming home. If any of the above is happening on top of that overdue first-check, it moves the appointment forward.

Dogs and puppies: what is normal, and what to call about

Most of what alarms new dog owners in the first two weeks is ordinary:

Crying at night — especially for puppies, especially for the first two or three nights.
Skipping a meal or two, particularly on day one.
Loose stools for the first day or two from stress and food change, provided they are not bloody or continuous.
Sleeping a great deal — puppies need 18 to 20 hours a day; adult dogs settling in may sleep more than they will later.
Occasional hiccups, sneezes, and yelping when they trip over their own legs.
Reluctance to interact for the first day or two, even in a friendly dog.

What is worth a call:

No food or water by the end of day one, or continued refusal by day two.
No bowel movement by 24 hours in, or no urine by 12 hours.
Vomiting or diarrhoea that repeats, or contains blood.
Breathing that is laboured or open-mouthed at rest (panting on a hot day is normal; panting when the dog is lying still on a cool floor is not).
Lethargy that does not lift after a nap — a dog that will not engage with you at all after resting is not shy, it is unwell.
A cough that sounds like a goose honk (kennel cough).
Any bleeding, obvious swelling, or the dog vocalising in a way you have not heard before, particularly when moving.
A shaking that is not from cold or excitement, and does not stop.

For puppies specifically, one extra threshold matters. A puppy that goes hypoglycaemic — sudden weakness, wobbling, cold to the touch, glassy-eyed — can decline within an hour. That is not a wait-and-see; that is a vet call now, and a small amount of honey or corn syrup rubbed on the gums while you get in the car.

Birds: what is normal, and what to call about

Birds are the species where the "hide illness" pattern is most extreme, because in the wild, showing weakness marks a bird as easy prey. A pet bird will look normal until it cannot look normal any more, and by then it is often very unwell. The consequence is that thresholds for birds are lower than for mammals: things that would be watch-and-see with a dog are call-the-vet with a bird.

Most of what alarms new bird owners in the first week is ordinary:

Reduced eating for the first day.
Long stretches of stillness on a single perch.
Silence — many birds do not vocalise at all for several days.
Fluffed feathers for short periods, especially in the evening.
Backing to the far side of the cage when a person approaches.
Sleeping up to 12 hours a night.

What is worth a call — and with birds, calls come earlier than with mammals:

No food eaten by the end of day one, or no water drunk by end of day two.
Discharge from the nares (nostrils), eyes, or vent.
Laboured breathing, tail-bobbing with each breath, or open-mouthed breathing at rest.
Fluffed feathers that do not resolve after a few hours, especially with lethargy.
Any bleeding, or a bald patch appearing after arrival.
Falling from a perch, or an inability to grip a perch.
Watery, discoloured, or bloody droppings that persist across multiple hours.
Sitting on the floor of the cage rather than a perch, at any point.
Any change in the baseline the bird had on day two or three, if it does not resolve in a few hours.

The last one is the one to internalise. With birds, the deviation from baseline is often the whole signal — the specific symptom matters less than that something has changed and stayed changed. A bird that was alert on day three and quiet on day four is not "settling in more"; it is a bird to phone the vet about.

Two things new owners get wrong

The first is treating "eating" as a single signal. In practice, food refusal is one of the most common signs of illness in every species — but it is also completely normal in the first 24 to 48 hours, when the animal is too anxious to eat. What matters is whether the refusal continues past the settling-in window (about 24 hours for a puppy, 48 for a cat, 24 for a bird), and whether the animal is also drinking. A cat that skips food but drinks water is much less worrying than a cat that skips both. A bird that skips both, at all, is worth a call.

The second is confusing quiet with calm. A newly arrived animal that sits perfectly still and does not react to anything can look extraordinarily well-behaved. It usually is not. Real calm involves movement — a cat exploring at night, a puppy following you across the kitchen, a bird preening on a perch. Total stillness in a new animal, especially combined with the head lowered or feathers fluffed, is often shutdown, not settling. Shutdown is a state the animal recovers from with careful, low-pressure presence; it is not a state to leave the animal in for days. If it does not resolve into visible normal activity by the end of the first week, it is worth mentioning to the vet.

The rule that covers everything else

If you are unsure whether to call, call. Vets get this call every day and would rather have it on a false alarm than miss the real one. A phone consultation is not the same as a full appointment; it is a triage, and the practice will decide with you whether the animal needs to be seen. Nothing is lost by asking.

The alternative — watching a symptom escalate over a weekend because you were embarrassed to phone — is the pattern that kills small animals in particular. Birds cannot afford the twelve hours it takes to feel silly, then reconsider, then phone. Puppies with parvo cannot afford it either. Adult cats and dogs have more reserve, but not so much more that it changes the principle.

In summary

Take three days to learn what normal looks like for the animal in front of you.
Do not treat one sign in isolation. Ask what else is stacked on it, and how long it has been there.
Species matters. What is 48 hours for a puppy is 24 for a bird.
Deviation from an animal's own baseline is worth more than any single symptom.
Quiet is not the same as calm. Total stillness in a new animal is often a warning, not good behaviour.
When in doubt, phone. Vets prefer the false alarm to the missed illness, and so should you.

The first weeks are hard partly because you are trying to make good calls with an animal you do not yet know. That gets easier. Every day you spend paying attention adds a little more to what you know normal looks like, and every trip to the vet in the first month — even one that turns out to be nothing — helps calibrate you for the trips that will one day not be nothing.