Avocado Tree producing in Wellington, New Zealand

It is commonly (though not universally) believed Avocados (Persea americana) cannot fruit in the cool temperate climate of  New Zealand's capital. 

This is a more cold tolerant variety, the 'Bacon' (it doesn't taste like Bacon, it's named after it's breeder). It grows happily in an unusually cold Central Wellington Valley,taking frost down to -3 C  (26.6 F).  I tried the more common variety 'Hass', usually reported to tolerate temperatures to around 0 C, it died the first winter (because most of Wellington is frost free 'Hass' might work in most places). If your first attempt at growing Avocados doesn't work, it might just be you need a more cold tolerant variety, 'Mexicola' takes frosts down to around -7 C (19.4 F) !

This tree started bearing after around 7 years, it flowered for three years without producing any fruit , it is only six feet tall. The fruits appear to be rather small, but very tasty, they took about a year to ripen. The flowers probably self pollinated, an example of the fact that Avocados do not need a pollinator in cool climates.       

Dovecote with rat-proof metal flashing

French Mondain and racing Pigeons in a Dovecote (pigeon-house) with metal flashing added after rats climbed up the neighboring Hops vine and beheaded squab (baby pigeons) to get to the grain in their gizzard. 

Rats can't grip on metal but they are lateral thinkers & acrobats I don't know for sure if this is full proof against them but seems to discourage, have not had any trouble with them since, feeding pigeons in the morning and learning to give them just enough grain so there isn't stuff lying around to attract scavengers like rats* is also helpful, along with old fashioned traps, placed where the pigeons can't reach(!).  

*Afterthought 5 years on. It looks as though accidentally leaving food out overnight may have also resulted in a stoat being attracted to the area, getting a taste for the feed, then stalking and killing an adult pigeon away from the dove cote to get more.  I'm guessing not a rat because they rarely attack mature birds. I suppose the bird may have died naturally and was then decapitated.

It appears to me pigeons are probably really suited to areas with open ground like lawns or pavement and possibly instinctively prefer this. They can see a predator coming where there are no bushes and herbs growing. They occur naturally in these sorts of places, not in bush or scrub or food gardens.  

** 10 years later update. I left this property 3 years ago. The racing pigeons have not been feed since but have continued to use the dovecote for breeding . I don't know where they've been getting food, perhaps from the city about 2 miles away. So it is possible to get squab for human food without feeding your pigeons anything, at least once they've gotten used to the dovecote and possibly as long as there is a city nearby but it would be worth trying in the country too.