Roof rats in a desert city
People are often surprised that a hot desert city has a climbing rat problem, but the reason is sitting in most back yards. Roof rats need two things: a route up and a place to nest. Citrus and mature shade trees supply the first, and in Tucson those trees are not decoration, they are what makes a 100F afternoon livable, so nobody wants to remove them. Fence lines, block walls, cables and downspouts all extend the network. Once an animal reaches the roof, it needs very little: a gap under a tile course, an unscreened vent, a soffit joint that opened as the building moved. The food supply is the second half. Citrus fruit is the signature: a roof rat hollows out the inside and leaves the rind hanging on the branch, which is one of the few pest signs you can identify from twenty feet away. The practical response is a sequence, not a product. Trim branches back several feet so the roof is no longer reachable, harvest fruit promptly and clear windfall, then close the roof line openings in metal. Doing the sealing while a citrus branch still touches the eave simply moves the animal along the roof until it finds the gap you missed.
What a 40F winter means for your plan
Rodent advice written for cold climates assumes winter does some of the work for you. Tucson removes that assumption entirely. With winter lows averaging 40F, there is no freeze that thins the outdoor population, no period where breeding stops, and no month when the pressure on your building drops to nothing. What lives in the neighborhood in December is still there in February, in roughly the same numbers, and it is still testing the same openings. Two things follow from that. The first is that trapping has an unusually short half-life here. Whatever you remove is replaced from a healthy outside pool rather than having to wait for a breeding season, so a trapping-only plan behaves like a subscription. The second is that sealing pays back across more of the year than it would in a cold city. A quarter-inch gap closed in Tucson is not protection against one autumn wave, it is protection against continuous pressure. Treat it as a permanent improvement to the building. The corollary is that there is no bad month to do the work, only bad conditions. Roof line work in July at 100F is miserable and slow, so if you have a choice, schedule it for the cooler half of the year.
Follow the water on a desert lot
The fastest way to find where rodents are working on a Tucson property is to stop looking for food and start looking for water. Twelve inches of rain a year and 38 percent average humidity mean natural water is scarce for most of the year. Everything that supplies it reliably becomes a fixed point in the animals' routine: drip emitters and the tubing that feeds them, a valve box that holds moisture underground, a hose bib with a slow drip, a condensate line off an air conditioner, pool equipment, and a pet bowl left out overnight. That explains a pattern people find puzzling, which is chewed irrigation tubing. The animals are not damaging the line out of spite or to sharpen teeth; they are opening it because it holds water. A mystery leak in a drip system is worth inspecting for gnaw marks before it is worth replacing. It also tells you where to concentrate. An inspection that only checks the kitchen and the attic in a desert city has skipped the part of the property that determines where the animals spend their nights. Fixing leaks, moving pet water indoors overnight and burying or covering exposed tubing are quiet, cheap steps that reduce pressure without touching a trap.
Sealing block, stucco and tile
Exclusion instructions written for wood-framed houses translate badly to construction here, so it helps to know what the openings actually look like on a Tucson building. Weep holes are the first surprise. They exist deliberately, to let moisture out of a masonry wall, and they cannot simply be filled. The correct fix is a cover or a piece of quarter-inch hardware cloth that keeps drainage working while excluding animals. Stucco is the second. It cracks and separates at corners and around penetrations as the building moves and the sun works on it, and those openings need patching with the right material rather than a bead of foam that will be chewed or degrade in a year. Tile roofs are the third and the most commonly missed. The gaps at the eave course and at ridge lines are easy to see from a ladder and effectively invisible from the ground, and they are exactly where a roof rat gets in. Closing them properly means fitting metal or purpose-made closures without blocking the ventilation the roof needs. Then there are the penetrations nobody planned: conduit, gas lines, cooling and irrigation lines. Each is easy to close in metal and mortar, and each is routinely left open for years.
Comparing quotes on what they actually change
Two proposals in this city can carry similar totals and describe very different amounts of work, so read the scope before the number. Ask first about heights. Because roof rats are a major part of the problem here, find out whether vents, tile gaps and soffit joints are included, or whether the quote only covers ground level work. That single question separates most Tucson proposals from one another. Ask whether openings are itemized with a material named for each. A line that reads exclusion and nothing further cannot be verified once the crew has gone, and it usually means less work than you pictured. Ask about the trees. If the plan does not address branches touching the roof, the sealing is being asked to do a job that trimming would make much easier, and the price should reflect who is doing that work. Ask what happens outdoors and around the irrigation, and whether outbuildings and stored vehicles are in scope. Finally, ask how many return visits are included and what triggers a further charge. A monthly station service that never touches the structure leaves you paying indefinitely in a climate where the pressure never lets up.