Frank wrote yesterday:
“Subject: Woodpecker damage on Galiano IslandHi Everyone .. in response to my earlier email about the possibility of woodpecker damage to our nesting boxes, Paul brought two of his boxes to me from Galiano Island, where they had been thoroughly pillaged by woodpeckers.One puzzling thing is that we have flickers and downies in our garden all year round, but never have any of them shown any interest in the nesting boxes. And the site on Galiano where the damage was done has escaped predation for years.Anyway, that’s just one more element of mystery surrounding the life of our bees.I’ve attached four images, one overall image of each of the two nesting boxes, and one detail of the worst damage on each one. It looks as if the woodpecker(s) managed to clean out the front end of every gallery, even those where it(they) did not enlarge the opening i.e. there is not a single gallery left with chambers right up to the front entrance. As far as I can tell, the first two or perhaps three chambers are gone, particularly in the enlarged openings.Just how much damage has been done won’t be evident until we open them up in November.It’s a jungle out there!Cheers,f.By the way, if you are wondering what the markings are on the fronts of the nesting box trays, there is some evidence that decorating them in some way makes it a little easier for the females to find the galleries they are working on. It’s not uncommon to see a female come back to the nesting box from a pollen-gathering or mud-gathering trip and enter a gallery, only to pop out immediately and go to a different one. Sometimes it takes more than two tries before she lands where she wants to be”Hi Frank- these are good examples of wood pecker damage and yes I receive these type of reports nearly every year.I think you are lucky a pileated woodpecker has not found these nests. These giants can demolish whole mason bee homes.From the look of the hole- depth, this woodpecker is likely to be the hairy or downy woodpecker. You mentioned that they have not been predated on before. this might be because of food availability. Early in the spring, I have seen damage from bears, where they actually lick out the pollen lumps! You would not think it would be worth it, but food must have been scarce at the time.One easy way of protecting the nest from wood peckers is the hang them facing inwards- in July when flight has ceased. Or you can protect them with a predator guard. Be aware that the predator guard has to be a good inch away from the face of the nesting tunnel. Wire screen is NOT too successful. I think wire is usually too thin for the bee to see the wire when they come barreling in towards the nest.If my nests are not protected in some way, woody woodpeckers are sure to find them here at home.Oh by the way- I think the nests are still good to use- and the trimmings will assist bees to orient towards their nesting tunnels. I would sand these rough chipped holes though.Margrietreply from Frank:Thanks for the suggestions of turning the boxes around or using predator guards. Dick S. was very faithful about turning his boxes around each season, I know. And I’ll pass along your comment about reusing the damaged trays. You’re quite right that except for the one that was enlarged to the size of a loonie, they just look like someone had taken a countersink bit to them I think that bird (or those birds) worked awfully hard for what they got!I’ll let you know what we find when we open them up in November.
It July 8/12. Is it too early to put a cloth bag over mason bee boxes to keep out predators?
We are in Comox, Vancouver Island. – Margaret
A comment on this blog asked for more pictures on candling cocoons.
Just today I candled 4000 cocoons. It seems like an awful lot, but when they are in petri dishes it is easy to do candle them- about 30 mins or so. I did see some duds that are of some interest. I call anything that is not a fully developed bee a ‘dud’. The percent ‘duds’ in this batch was 2.5%. Anything under 5% is excellent. But even with 107 duds there are some interesting ones. Few had fully developed parasitic wasps- ready to emerge in spring. Others were bee larvae that had not completed development into an adult. In the next day or so I will take some photos and put them on this blog.
I was teaching a group of people about candling the other day. It is a straight forward procedure but the conditions have to be right. The room that you do the candling in has to be completely dark- a bathroom without a window for example. Any extra light besides the flashlight is too much light and you cannot candle the cocoons.
Frank mentioned removing mites with a ‘large stainless steel colander’. The best colander is not just any colander. More about this later, but first, lets back up a little and I will explain my rationale for removing mites.
Getting rid or removing ALL mites from cocoons is difficult. I think the main aim is to remove the majority of mites, so that mason bees have a better chance of producing healthy offspring. Even if all mites are removed from harvested cocoons, there will be the occasional mite covered wild bee that arrives from within the local wood. These mites are spread successfully ensuring mites are always around. The best that anyone can do is to remove the majority of mites from harvested cocoons. This give mason bees a better chance in producing healthy offspring rather then mites.
Washing with water, removes adhering frass and the majority of loose mites. After washing, there are still lots of mites in amongst the threads of the cocoon.
These mites are best removed by friction. I have found the most successful way to remove these mites is to gently roll them over a METAL window screen stapled to a frame. Another way is to gently roll them around colander with a metal screen (NOT PLASTIC, NOT STAINLESS). Plastic and stainless steel do not have the abrasive quality of metal screen.
This can be done in two stages. First wash with the appropriate colander under and in running water. Second, when cocoons are dry, roll them over another screen to get the remaining mites off.