Life near the bush line: possums in paradise

Greg and Serena Trillo had been on the lookout for another lifestyle block for a while when they were invited to view this 30 hectare property, north of Katikati. It appealed to them on a number of counts but it was the views from the back of the block that made them realise they had found the perfect property. They were smitten. And no wonder.

From the highest point on the property the views are spectacular – the northern end of Tauranga Harbour and a pine covered Matakana Island in the middle distance with distant views of Karewa, Mayor (Tuhua) and Motiti islands. A slight shift to the right brings the silhouette of that iconic Bay of Plenty landform, Mount Maunganui (Mauao), into view.

 

If you’ve got views then there’s usually a hill or two somewhere. With the exception of two front paddocks down by the gate, the block is hilly, sprinkled with small tree filled gullies before rising steeply to the bush line. While this sort of property would be suitable for grazing sheep the Trillos have chosen to run cattle instead – mainly because that’s what they are familiar with, after having grazed cattle on their previous block. The cattle share the farm with three much loved horses (all officially retired)

When they first took the property over Greg had a really good go at the possum population – traps yielded 15 or so from the small stand of mature pinus radiata by the henhouse and 200 from a single trapping line in the bush at the back of the farm.  Clearing the block of possums sometimes seems like an impossible dream. “They keep on coming back” says Greg, “By the chook pen there I put out half a dozen traps, got rid of them and a week later they were back again.”

This area has some beautiful patches of bush but it also hosts a large possum population. Greg is keen to minimise their impact on his own land and lays traps through this bush line area, as time allows. He often works off site for several days at a stretch so there’s not always time to maintain trap lines.The abundance of possums is due, in no small part, to the fact that a section of the Trillo’s property backs on to Department of Conservation (DOC) administered land – the northerly end of the Kaimai-Mamaku State Forest Park.

DOC oversees all trapping and pest control activities on its land – it’s very much a regulated activity. Permits are valid for a three month period and relate to specific blocks of land. It’s a practical system that works well for both land owners and the Department of Conservation.

However, at the end of the day, trapping is a labour intensive exercise. Laying toxic baits such as Feratox would be a whole lot easier. However, as Greg points out, there are a few administrative hoops to jump through before you can to do this …

 “We could apply to use the product Feratox up there -- which we might do at some stage. We would install a bait station network and fill them with prefeed pellets and approximately 5 Feratox pills, depending on possum numbers … But [if we were to do that] we would have to make an application to the Ministry of Health and Department of Conservation. We would also need to notify all our neighbours -- I know one neighbour would be all for it because she’s got possums climbing all over her roof … “

There have been several rounds of trapping since they first arrived on the property but there’s been possum sign outside the henhouse lately so Greg knows another round of pest control is due

Serena realised that the possums were well and truly back when she found one having a nap inside the henhouse. Not a bad idea from the possum’s point of view but the chooks weren’t that thrilled and nor were Serena or Greg.  While it’s possible that the hens are facing a straightforward, single predator, possum problem, Greg, who is an independent pest control contractor, knows there could be more than one predator active in the area. This time he has decided to place Chew Cards both in the stand of pines around the henhouse and in the bush at the back of the property. Bite marks on the cards will give a clear indication of which predators are in the vicinity.

After nailing cards to trees at “hammer height” from the ground, Greg makes a blaze of plain flour on the tree trunk directly beneath the card.  He has used the flour method before and reckons that the unfamiliar scent and the visual marker help lead predators to the cards -- and in doing so increase the chances of a more accurate reading of the local predator population.

It’s difficult to know whether Serena and Greg‘s dog, Joyce, is as dedicated to the pest control cause as they are or just likes chasing things. Whatever the case may be, she is, as this photo testifies, a bit of a star.

She successfully routed this possum from the scrub near the house.  It’s bailed up at the top of the remains of an old mamaku trunk. I didn’t ask what happened to the possum after these photographs were taken ….   

It has been an afternoon well spent. Now that the groundwork has been done it will be interesting to see what the Chew Cards turn up.

The results from the CTC cards are in …

After 7 days Greg checked on the cards. As predicted, possums were present – but so were large numbers of rats. Which was a bit of a surprise.

While most predators gnaw or bite the cards possums use their teeth to scrape bait from the centre of the card towards the edge -- the pressure pushing the bait out of the card cavity.

Rats, on the other hand, simply eat the card to get to the bait … 

 

Date of visit: 21/4/2018