Spiders in Nestboxes and as Food

From: Michelle [mailto:shell7"at"cox.net]
Sent: Tuesday, February 08, 2005 12:53 PM
Subject: Spiders in nest boxes

I'm wondering if these spiders are bad for the bluebirds...they are black with some white, jumpy spiders, some with green eyes, and they make a real thick, cotton looking web. We've always called them jumpy spiders. Are they harmful to the bluebirds, and will it prevent them from nesting if they are in the box?
Michelle Martin
Port Allen, LA

Hi, Michelle,

Not only will spiders not harm Bluebirds, there are indications that spiders benefit Bluebirds and other birds by consuming tropical fowl mites and other nest parasites. I don't know about jumpy spiders specifically but spiders are almost always beneficial.

I'll have look around for studies (some are still ongoing) about leaving old nests intact rather than cleaning out the nest boxes. There are some indications that, by cleaning out nest boxes or using insecticides like Sevin, we are killing or driving away spiders that might otherwise naturally control parasitic mites.
TBN is involved in at least one study. There's also anecdotal evidence. Read "Why nest cups should be emptied and cleaned between broods" in the middle of the page http://www.americanartifacts.com/smma/per/b4loc.htm

I have a couple of identical nestboxes, one with a carefully preserved 2004 nest. The other is spotlessly cleaned, wiped with bleach solution and dried. Which will the Bluebirds (and Tree Swallows and ???) prefer? There's at least one wee spider resident in a crack in the unclean nestbox and another who set up housekeeping on the underside of the box. The clean box is, well, very clean.

I've rarely cleaned out a nest box that didn't have spider sacks stuck in the top corners and under the nesting material. I have neither seen nor heard of spiders harming any bird. Unless a spider fills your nestbox with a web that might discourage nesting, I recommend letting spiders coexist with your Bluebirds... who may find the spiders tasty if insects are scarce.

Take care,

R J 'Tree' Greenwood
Catlett VA

Keith Kridler Mt. Pleasant, Texas

Tree Greenwood gave an excellent reply to this question. This is one of the species of "Black Fly Spider" that is very common across the southern states. These jumpy spiders do not spin a sticky web to snare their victims but anchor their bodies to a surface with a strong web just before they leap and grab an insect.

This is the spider that someone at Cornell mentioned that they wanted nestbox monitors to copy the insects nest looks by installing cotton balls in nestboxes to see if this would frighten away wasps and other insects. (I don't think cotton balls will work.) This fly spider grows to be fairly large (about and inch long) and they spin a white tent or really a "sleeping bag" that they hide in somewhere around the nestbox. These hiding tents very much look like a small ball of cotton sometimes.

On occasion I have seen these spiders eating a full grown paper wasp that they have killed. I just took some pretty good photo's last weekend of a species of mud dauber nest with the ends of the tubes filled with these black fly spider sleeping tents. As these mud daubers and spiders have over wintered in the same nestbox I would assume as the adult mud daubers slowly chew their way out of the mud tunnels that they would be very easy prey for a fast spider.

My boxes are filled with these white cottony tents and I will watch closer to see if paper wasps avoid these nestboxes or use the new nestboxes more often that we have installed that do not contain fly spiders yet.

Blowflies would make a good sized meal for spiders. These spiders like to hide in a hole or tube 3/8">1/2" diameter is good for adults, 1/4">5/16" is good for young spiders. You can attach these tubes to the bottoms of the nestboxes or inside the box on an interior wall.

If you want the photo's of the mud dauber nest to use or pass on drop me a note. I have them in 2 MGB for a slide presentation or about 60KB for web pages. KK

Hello Tree, Thanks so much for the information and link to that page. Very interesting! Looks like I'll be leaving the spiders then. No need in taking them out of the box if the birds eat them anyway, or if they don't, the spiders are still not harmful. I did a little research on the "Daring Jumping Spider" (this is what I have in the boxes), and seems this spider has birds at it's predator, so that's good to know. Here is a link to the spider's photo and info, if anyone is interested.
http://www.fcps.k12.va.us/StratfordLandingES/Ecology/mpages/daring_jumping_s
pider.htm
Thanks for helping me out!

Michelle Martin
Port Allen, LA

Tree,

Thank you for this post. I learned something. Now for a question. HOWR use spider egg casings interspersed throughout their nests and I am now wondering if it is possible that the spiderlings hatch out and help control mites on the nestlings. Have any studies ever been done to look at this possible symbiotic relationship to your knowledge? Do scientists know why HOWR use spider casings in their nests?

Thanks,
Paula Z
Powell (Central) Ohio

What are those of us to do who are terrified by spiders? It isn't rational, or reasonable -- it just IS. I'd rather pick up a snake with my bare hands than have a spider within six feet of me. I'd go for counseling, but I'm too old. ;-)

Cher

Cher and Lana and Bluebirders:

Spiders are so common that chances are excellent that there is one within a few inches of you wherever your at! Insects in the house have to go but I always put a spider in a house plant or a window sill.
The only one in the house to avoid is the Brown Recluse. Learn to id it and nail it. The rest are all friendly - and benefical - little critters, as has been pointed out in several posts.

I'm so glad that you all agree that they are similarly beneficial for the nesting cavity birds too.
We probably destroy a lot of spiders when we sanitize are nest boxes with clorox.
I've never suggested that in my presentations, etc., but if a person feels like doing that it won't make any difference in the grand scheme of things...

Good birding, Larry H. Joplin MO.

Keith Kridler Mt. Pleasant Texas
Many of the wren species feed their young spiders so installing nestboxes in places the Carolina Wren prefers to nest will help thin out the spider population. (Not that you will notice!) A gallon paint bucket laid on it's side or a cardboard box about this size with a 3"x3" hole in one side of it placed on a shelf in a carport will make a great home for this wren. So will a fern in a hanging basket on your porch.

There are three different species of mud dabbers (solitary wasps) that all feed on many different species of spiders. Then there are smaller solitary wasps that drill into these completed mud nests and lay their eggs on the mud dabber larva that will in turn eat the mud dabber young that are eating the young spiders in the mud cells.

There are solitary wasps that bore out tunnels to nest in the ground and also paralyze spiders or other insects with their sting to create a food source for their young. Some will even kill the tarantula spider or other very large wolf spiders. I seem to recall that more than 600 different species of solitary wasps and bees have been identified living in Texas.

There is a species of "funnel web" spider that will use your nestbox and this species will spin a web that from a distance looks like someone has placed a white cotton handkerchief in the entrance to your nestbox. This spider suspends the solid web mostly flat and it acts like a trampoline to capture insects that are falling to the ground. When an insect "bounces" on the trampoline it alerts the spider who is resting down in the funnel or tunnel inside the nestbox and it will run out and capture the small insects and then scamper back down into the safety of the funnel/tunnel.

When cleaning out nestboxes it really is a good idea to wear a pair of light weight rubber gloves that cover your hands and wrists. A wonderful tool for women to use while removing old nests and scraping out wasp nests or swatting an occasional spider, is a LONG handled spatula normally used for flipping burgers. Most people have an old rusty one out on the grill or in the bottom of the drawer. Spray paint it so you don't mix it up with your cooking tools.

Macho men can use those short handled paint scrappers for nestbox cleaning.
Don't forget to put in some of those cleaning wipes in your car or back pack for spot cleaning your hands occasionally. KK

Thanks for the spider comments. I also have at least several boxes taken over each fall by one of these mud dabber species of spiders -- perhaps because my trail is in a river flood plain.

I have often wondered how long you have to leave these tubes in place so as to avoid killing the occupants? I cleaned some out last spring (not easy to do incidentally as they were constructed with the heavily weathered clayey soils of in this older landscape which pre-date the Wisconsian glaciation).
But in the process of removal I think I ended up killing a bunch of gestating spiders -- too bad -- I'd like to avoid that in the future.

Concerning spiders in general arachnids are an important food source for Eastern Bluebirds especially in the first week after hatching when soft food is sought by the parents. The wolf spiders (lycosidae group) are often an important part of the diet for Bluebirds. For details see either of these excellent studies of Bluebird nest box food items: Bay & McGaha. 2000. Proc.
Okla. Acad, Sci.; 80:129-132 (done in Oklahoma) or Pinkowski. 1978.Wilson
Bull.;09:84-89 (done in Michigan).

Bernie Daniel

Dear Bernie,
For those of us who are not familiar with referencing scientific journals, would you please share with us where we would find the articles on bluebird nestbox foods? Internet? Local library? University library?
Thanks!
Pauline Tom
Mountain City (no mountains) TX

Hi Pauline -- I will attempt to scan in the articles and post them as .pdf files next week. Meanwhile, I tonight I will find some summary tables of food items -- from these papers -- that I often use for Bluebird talks and attach them to an email to the listserver. Most would probably just want the information rather than having to read a technical paper. Bernie

Keith Kridler Mt. Pleasant, Texas
There are three main species of mud daubers that build large clusters of mud tunnels filled with spiders. At this time of year the mud dabber should be in a black or dark brown case waiting for warmer weather to hatch out. They pretty well time their hatching to when there will be a larger number of adult and mid sized spiders for easy hunting.

They thrive in the dog days of summer when the temperatures remain above 75* even at night. If you break open a nest of mud daubers now and find only spiders then you can be pretty sure the single egg did not hatch or the larva of the mud dabber (large yellow grub) was killed and eaten by another predator.

The mud dabbers sting the spiders as they catch them and this pretty well paralyzes the spiders. IF you handle these spiders they can or could still bite as they move in really SLOW motion or at least wiggle their legs. By not killing the spiders they stay fresh so that the larva of the mud dabber does not have to eat dried up spiders....When desperate for fish bait I would use these spiders in winter to catch sunfish. They would probably make good food for wrens in the dead of winter.

Spiders are starting to hatch out in my area and the small "spinners" webs are showing up in trees and grass on these cool dewy mornings. I saw the first Crane Flies yesterday while gassing up the car. Fresh insects hatching out provide the final piece that bluebirds need to begin building nests and laying eggs. KK

-----Original Message-----
From: Bernie Daniel [mailto:bdaniel"at"cinci.rr.com]
Sent: Saturday, February 12, 2005 8:53 AM
To: Keith & Sandy Kridler; BLUEBIRD-L
Subject: Re: When will the mud dabber "hatch" out -- more on it.

Thanks Keith

The mud dauber was the bug of the month! -- in July 1996 -- see link for nice pics.

http://crawford.tardigrade.net/bugs/BugofMonth22.html

I copied this little section because I found it interesting. I have not researched it but from this little write up I would guess that the mud dauber (also called dirt dauber) is actually more of a solitary bee than a wasp. Maybe related to the bumble bee?

Here is the text from the page: -- written from a western USA perspective.
"Although I think of mud daubers as wasps, all sphecids are more closely related to bees than to the vespid wasps (Ross & Matthews 1991). There are two genera and only five species of mud daubers in the U.S. In the west, there are only two species: Sceliphron caementarium, our hero, and the blue mud dauber, Chalybion californicum, which has a blue metallic body and bluish wings (Bohart & Menke 1976). Strictly speaking, the blue mud dauber, Chalybion, doesn't really carry mud. It does, however, carry water and re-engineer abandoned cells left by Sceliphron (Bohart & Menke). Chalybion also uses plant stems and cavities for nests. An opportunist, one might say." --Louis Kulzer of Seattle

Bernie

Keith Kridler Mt. Pleasant, Texas
Mud Daubers hunt or search for spiders that they grab and then sting to paralyze the spider for a future meal for their young. They then grasp the spider gently with their large jaws that open and look like a set of antique ice tongs. They help hold the spider if it is large with their front set of feet. They fly back to their nest and push the spider into the tube packing it into the tube with the flat face of their head and fly off to find another spider.

There is a black and yellow species that builds a series of small tubes glued one on top of the other that specializes in hunting the young of those Orb Weaver night spiders that spin the big sticky round webs. Their young chew out the end of the tube when mature and the mud nest looks like someone drilled holes for a closely space peg board. This is a large slow flying species and would be a "Goose" if it were a bird or a bomber if an airplane.

There is a totally black mud dauber that can hover like a hummingbird but has the strength and speed of a "peregrine" (I called these Mig 21's back in the late 60's) and the female builds a long single tunnel that can hold 8 or nine single cells laid end to end and she leaves her mate to guard the tunnel while she goes and gets another ball of mud or goes off in search of another spider. When a certain number of spiders are packed in there the female seals off the longer tube with a mud partition. The funny thing about this is that the open tube is always pointing down which protects the nest from rain but I guess the male stays to keep spiders from falling out or to keep ants from raiding the spiders. This species captures a lot of young "Garden Spiders" the ones who grow up to be very large and build a huge orb in brushy areas and have that large white zig zag center of the web that they hunt from. These young drill out holes through the dome top of the tube and you should see about a 1/4" hole every 1&1/2" if all of the young survive.

There is a third black mud dauber that builds a nest like the first one only they cheat when collecting mud. They often fly to a water source and enter an area with a lot of old mud dauber nests where the female will regurgitate the water on an old nest, soften the mud and then chew it and work it into a ball and fly off to her nest. This way she can make more trips and build quicker because there are a lot more water sources than there are suitable mud puddles.

This species hunts more from the ground and would be the "House Wren". It lands on the ground runs a few steps, flashes it's wings and then runs on a little further. It hunts very similar to a Mockingbird actually. Depending on the area and the time of year this species of mud dauber will sometimes stuff its food cells for the young with more than half of the spiders being young black widow spiders! At night this species will congregate in a communal roost somewhere out of the weather and in late summer more than 500 can be found coming to the night roost and sleeping on the underside of some object massed together like a colony of bats.

Anyway these insects are "cavity nesters" and just like bluebirds they spend their whole summer building nests, guarding the nests from predators, carrying food for their young very often you will see the last mud cell half completed or half filled with spiders being raided by ants. If you watch Garden Spider webs you pretty often see that the adult spiders take their toll of the "wasps" that were hunting them when THEY were young. Early humans probably watched species of mud dabbers working the mud and the type of mud it takes to make pottery or bricks is the same type mud these insects use.

.... KK

Keith Kridler Mt. Pleasant, Texas
Tarantulas in nestboxes! How many of you reach into a nestbox you have not looked in, but feel around to "see" with your fingers what is in the box:-)) A Tarantula could bite a baby bird if it was hungry or give you a good pinch if you made it mad!

In the south the Brown Recluse spider is VERY dangerous to humans (Shawn just said he found another one in his bathroom this morning) and these spiders are sometimes found in a nestbox. They are a type of Wolf spider and do NOT spin a sticky catch web for prey but prowl around in search of food.
They are normally smaller than 1&1/2" across their legs and body. A single bite from them would kill a small baby bird. Their venom begins to dissolve soft tissue and flesh with antibiotics used to stop the wound growth.

Black Widow Spiders are commonly found in nestboxes but they spin a very strong web of individual fibers that are "sticky" where they connect to the walls or bottom of a box where insects will walk into the base of the web.
They prey mostly on crawling insects. Their venom affects the nervous system and will REALLY make a human sick, probably lethal for a small bird.

The Red Widow Spider is now found in Florida, an imported Australian cousin to our Black Widow.

A funnel web spider often will use a nestbox. They are not dangerous and their web often plugs up the hole on the nestbox and resembles a dirty gray handkerchief spread outside the nestbox to catch insects falling through the air.

There are lots of other types of spiders that might be in boxes that are not dangerous to the birds or humans. Use caution and "Look Before You Reach"
into a nestbox. KK

From: bookfanaticef-bluebird"at"yahoo.com [mailto:bookfanaticef-bluebird"at"yahoo.com]
Sent: Friday, May 13, 2005 12:46 PM
Subject: Re: Spiders in nestboxes--and scorpions, too

Another note on spiders--

I frequently find Jumping Spiders in my EABL boxes, which can often be quite large (thumbnail-size) & look dangerous & almost tarantula-like sometimes, but to my knowledge, they are harmless to both the birds and humans. They often have a small "web" that is thick and cobweb-like in a box corner or along the edge of the bird's nest, but I'm pretty sure it's actually an egg case--jumping spiders don't hunt with webs. As their name implies, they walk around & jump after their prey--usually insects and other things smaller than themselves. A couple times I haven't been able to check boxes for a week or two due to weather, and find a jumping spider has comfortably taken up residence, without causing the resident birds & their nestlings any apparent problems. I've been removing the few I can actually catch (their spectacular jumping ability means they usually get away), but I wonder if I should continue doing so--since they seem to pose no! danger to the birds, I've been wondering if the jumpers actually help keep down the populations of parasites & other insects inside the box.

Brown Widow spiders are also found in Florida. I believe they are natives, but am not sure. They also have the charcateristic globular abdomen w/red hourglass, and have the same haphazard "cobweb" web as the Black Widows. They are mottled brownish in color, and superficially resemble the more common and generally harmless "House" or "Garden" spiders (which don't have the red hourglass). I once went into a bathroom in a park that had dozens of spiders--I at first thought they were harmless House spiders, but the next time I went I brought a flashlight because I am curious--every single one I looked at was a Brown Widow--I was much more careful where I put my hands after that! Yikes!

And a couple times, I've actually found small scorpions inside a nest box (thankfully empty of any nests). I knew we had scorpions in Florida, but had never seen a single one until then. They definitely had to go. One box had 3 scorpions resting in there!
Elizabeth Farley
Gainesville, FL

Trish - Frankston, TX
Morning, Keith!! I'm sure I am in good company when I say, I really HATE spiders and tarantulas. Having grown up in southwestern Oklahoma and now living in Texas for 16 years, I have learned not to reach into any dark space without looking first....or to put on a shoe without shaking it out first. I can't tell you the number of times a scorpion crawled out of my shoe with shaking. My first experience with tarantulas was as a child when I threw a rock at one, not knowing she had hundreds of babies on her back, which I then had to clean off my arms. That's an experience I have never forgotten! A question, though....if you use the bird cage disinfectant spray between nests, would that discourage spiders as well as other insects, ya think?

From: T Williams [mailto:tawword"at"yahoo.com]
Sent: Friday, May 13, 2005 7:12 PM
Subject: Re: OT Brown recluse spiders in the South

I live in the South, and I am terrified of brown recluse spiders and black widows. Many people end up with amputations because of brown recluse bites. Take a look - I found this link at the Discovery.com Web site. I have seen even worse pictures, but I can't seem to locate the site now:

http://www.brown-recluse.com/bitephotos.html

From: David Gwin [mailto:David.Gwin"at"cityofcarrollton.com]
Sent: Thursday, March 23, 2006 10:16 AM
Subject: RE: wire platforms under bluebird nests

Morning, Melissa:

Regarding spiders ... most spiders that you will find in your boxes are beneficial for you and the bluebirds! They prey on all the insects that would normally hinder the birds and their reproduction and even you while you are trying to monitor the box throughout the season!

Over the years, I have observed numerous species of "bad" insects tangled in their webs. Once you get used to them and learn to appreciate them, they are just as fascinating as the birds!

In fact, during the Fall and Winter here in North Texas, I have many funnel spiders that actually use the hole of the box as an architectural feature from which to orient their webs. Once the unsuspecting insect enters the whole of the box ... BAMMMM ... he's lunch!

I also have an old-timer naturalist friend that claims that these species of spiders provide the bulk of spider webs for hummingbirds to build their nests in the Spring each year! Spiders are amazing creatures. Just give them a chance and they will definitely help you to "monitor" your boxes!

Have a great day,
David

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