Animals difficult to breed in captivity

[FBBird]

For birds I would say all those that feed on flying insects are practically impossible - swallows and swifts for example. Some bee eaters which also hawk for insects have been bred but very rarely. In fact insectivorous passerines in general are difficult - most are highly territorial and can often kill each other is not in breeding condition and a compatible pair. That is not to say they are impossible - many thrushes are so regularly bred that there are colour mutations in aviculture of European Blackbird, Song Thrush and others - but it is very time consuming and labour intensive.

While I would agree Swifts are probably unsuitable aviary subjects due to their very aerial lifestyle, various Hirundines have been captive bred, and Barn Swallows in particular seem to do rather well given sufficient flying area.

 

[Zoovolunteer]

While I would agree Swifts are probably unsuitable aviary subjects due to their very aerial lifestyle, various Hirundines have been captive bred, and Barn Swallows in particular seem to do rather well given sufficient flying area.

I was unaware of any captive breeding ofm hirundines - do you have any links? I would like to follow up on this

 

[FBBird]

I was unaware of any captive breeding ofm hirundines - do you have any links? I would like to follow up on this

Look in the Avicultural Magazine online index and get back to me if you get stuck. Welcome Swallows in Australia, Barn Swallows in France, and at least one Martin species.

 

[FBBird]

I was unaware of any captive breeding ofm hirundines - do you have any links? I would like to follow up on this

A quick google search reveals Wuppertal Zoo as holding Barn Swallows over many years, having bred those and House Martins. Welcome Swallows have been bred in Australia

 

[DesertRhino150]

I was unaware of any captive breeding ofm hirundines - do you have any links? I would like to follow up on this

There are barn swallows kept in the okapi aviary at Rotterdam Zoo, which have bred in 2015, 2016, 2017 and 2019 according to Zootierliste.

The ZooLex page for the exhibit includes a photograph of the nesting cups used in the exhibit for them:
ZooLex Exhibit - Congo Forest - Birds and Okapis

 

[OrcinusOcean]

Multiple people have already pointed out cetaceans in general as difficult species to breed, but I'd like to mention specifically Pilot Whales.
Despite being held in captivity since the 1940's, you can quite literally count on your fingers the number of Pilot whale pregnancies that have happened. To my knowledge there's never been a Pilot Whale calf conceived captivity. There's been a small handful of pregnant animals captured who suffered miscarriages pretty quickly, back in the 50's-80's. There's also been a few hybrids that were conceived in captivity, one in 1981 with a Bottlenose Dolphin at SeaWorld (who was either a near full-term miscarriage or died a few days after birth) and, most recently, one in 2022 with a Pseudorca at the Taiji Whale Museum, who lived to at least 5 months old and MAY still be alive, though the language barrier and the museums tendency to not report deaths makes it very difficult to tell for sure.
(also of note, the mother, a wild-caught Pilot Whale named Gita, did not nurse her calf for at least a month, after which staff stepped in to hand-feed it)
Regardless, this 5 month old Pilot Whale hybrid is the best success anyone has ever gotten at breeding pilot whales in captivity over 80 years.
Despite being species that's pretty commonly kept, that adapts decently well to captivity - for cetaceans, at least - they simply do not breed. There is zero record of any pilot whale ever conceiving a calf in captivity, let alone carrying it to term.

I have to reply to this, because it's a common idea even among proponents of cetacean facilities - but name me one, two or three facilities that have actually kept mature male-female pairs or pods of pilot whales for any length of time.

Marineland of the Pacific had big long-finned bull Bimbo along with several juvenile or subadult female short-fins. He was released, and they ended up with only females.
Most facilities who kept them had only one, kept with dolphins.
SeaWorld had a lot of rescues that died soon.

I don't have the same exhaustive lists of every pilot whale as I do killer whales (solid info is just much more available online for the latter), but I have searched and searched and simply could not find a single facility that kept a solid pod, or long-term mature pairing of pilot whales, anywhere, at any time.

SeaWorld was just getting there with Ava + Piper + Ace + Argo, but now the males are gone, and it would really surprise me if they did not keep the females on birth control (the management don't want that social media controversy of baby whales, as we've seen).

So saying "pilot whales don't breed" is like saying "killer whales don't breed", in 1980. We've had pilot whales since the 1950s (even further counting that one in Japan in the 30s), but since no real effort has been made to actually keep the species as anything but a sideshow attraction or rescue+rehab stranded animals, it's not a fair assessment to say they can't breed in human care.

 

[peruvianbirdie]

Speaking of SeaWorld, I feel like penguins in the Aptenodytes family (emperor and king) seem to be rare to hatch with the latter being often successfully reared for the first time for some facilities like SEA LIFE Melbourne. It took SeaWorld a decade to have their latest Emperor chick back at 2023.