Has anyone who's set up Martin houses actually noticed a decline in the mosquitos? Thinking of setting one up where we launch our boat because they're awful there

...better mount several bat boxes too...and NOT randomly.
https://batworld.org/bat-house-information/
and
https://batmanagement.com/blogs/bat-roosts/how-to-choose-a-bat-house-location should help

My wife is from Mich and i spent 4 years there at college so I sympathize with your plight. Pray for a good crop of Dragon Flies. They prey on mosquitoes from lava (in the water) to adults and BY FAR impact the mosquito population negatively more than 1000 Bats and Martin do. So keep your streams and ponds clean of oils and hope a good crop of predators shows up soon.

Martins like to eat dragonflies. Seen them bringing them in to the chicks many times. Is there a quandry here?

I have both martins and dragonflies. We also have a healthy population of deer flies and mosquitoes. Before the Martins the dragonflies couldn't keep up. Dragonflies seem to prefer the deer flies over mosquitoes.

The Martins showed up last year and again this year. 2 years now we have been able to enjoy our outdoor space even in the evening.

I think I have video somewhere.

We have martins and two barns full of barnswallows a 3 acre pondless than 100 yards from my house and an acre pond 300 yds from the house we have almost no mosquitoes or deer flies

Couldn't find the video.

Bat houses are your best bet to rid mosquitos.

theres a martin house about 300 yards east of my house and a 2nd one about 1000 yards west. the one to east has been active for a good decade and the one west maybe 4 years. mud puddle of lake sits sorta in between. lots of bats in the evening, but there is no shortage of skeeters, not sure if it would be noticeably worse without them but sure cant say its a skeeter free environment. there's bunch of stuff online about attracting them etc.

hit the nail on the head/

Invite em all to free housing and food......martens, skeeter hawks, bats, all of them. They all add up to clean skies.

https://www.thespruce.com/fun-facts-about-purple-martins-387110
Purple martins do most of their feeding between 160-500 feet high (50-150 meters). Because of this height, mosquitoes make up only a small portion of their diet, despite rumors that the birds can eat up to 2,000 mosquitoes per day. They could consume that many, but mosquitoes are not generally found at a purple martin's feeding height in such large numbers.


http://www.mosquitoreviews.com/purple-martins-bats.html
Purple martins have gained a reputation as natural mosquito predators, and they do eat adult mosquitoes, but they eat most other kinds of flying bugs, too. No research has shown that mosquitoes are more than 3 percent of their diet, according to an article in Missouri Conservationist magazine. [1] The results seem logical, since martins catch insects during the day while flying high in the sky, but mosquitoes usually fly close to the ground looking for prey to bite, and are most active after dark. Claims that these birds can eat 2000 mosquitoes a day are based on a hypothetical diet eating nothing but mosquitoes--something that no purple martin actually does.


http://www.wbrcouncil.org/Departments/Mosquito-Abatement/Natural-Mosquito-Killers
The purple martin is an excellent example of a natural mosquito predator who's mosquito controlling ability has often been grossly exaggerated. Yes, they will and do eat mosquitoes but nowhere near the amount that would be needed to consider them effective at controlling mosquito populations.

That is interesting since what I'm seeing is them feeding 30' and below.

Early morning and late evening/dusk.

No one ever said they don't. But that's not where they spend the majority of their time feeding.

The reading suggest their impact on mosquitoes is "grossly exaggerated." If you want to get bit at my place you'll have to bring one with you. lol

Nobody doubts that Hobbie, just saying it most likely is due to something else not the birds.

I've been there 13 years and things have been unchanged, including the swamp 100yds away except for the birds the last 2 years, so we'll just have to disagree.