Pigeons were nesting four floors up. We rappelled down and screened every downspout.

Birds in the downspouts, and nobody could get to them

The owner's complaint was specific: pigeons were nesting inside the downspouts, and the sound was coming through the wall of the top-floor unit. The birds had also worked their way in under the fourth-floor deck. This is a common pattern in Old Town — a well-kept brick building where the only unmaintained square footage is the part nobody can reach.

Every downspout on the building starts at an open conductor head: the sheet-metal box at the top of the run that catches water off the gutter and funnels it down. To a pigeon, that box is close to perfect. High walls, a solid floor, a roof over it, and forty feet of air between the nest and anything on the ground. Left alone through a season, it fills with nesting material until the downspout stops draining and the overflow starts running down the brick instead.

Removing the nests solves nothing on its own. The birds come back to the same opening within days. The only durable fix is to close the opening to birds while leaving it fully open to water.

Rigged from the roof, screened on rope

1. Anchors set and inspected on the roof. Two independently anchored lines per technician — a working line and a backup line — rigged and checked before anyone went over the edge.
2. Edge protection at every contact point. The parapet coping and the roof edge were padded so the rope never bears on a hard corner, and so the building's stone and membrane are not marked by the descent.
3. Descent to each opening. The technician rappels to the conductor head, ties off in a working position, and has both hands free at the work — the same industrial technique used on high-rise facades, on a four-story building.
4. Nests cleared, openings measured. Each head was cleared of nesting material and measured in place, since sizes vary across a run even on one building.
5. Stainless screens fitted and fastened. Each screen is a formed hood of expanded stainless steel mesh, set over the opening and fastened to the metal head and the brick so it cannot be lifted off by wind or by a bird working at the edge.
6. Photographed before and after. Every opening was documented from the rope, so the owner can see exactly what was up there and exactly what is there now.

What the screens are, and why they don't cause overflow

Each screen is expanded stainless steel mesh, formed into a five-sided hood and fitted over the mouth of the conductor head. Stainless because it sits in standing water and Chicago road salt for decades and cannot be the part that fails; expanded mesh because it is rigid enough to hold its shape without a frame and open enough not to restrict flow.

The usual worry is that a screen will turn into a clog. It doesn't, as long as it is sized right. The hood is fabricated larger than the opening it covers, which means the total open area of the mesh is several times the cross-section of the downspout throat below it. Water never sees the mesh as a restriction — the pipe is the bottleneck, not the screen. What the mesh stops is anything too big to pass through it: birds, nesting material, and the leaf litter that used to wash straight into the pipe.

Fastening matters as much as the mesh. Screws through the flange into the metal head and the mortar joints mean the screen cannot be lifted by wind, and a bird working at the edge finds nothing that gives. Gutters and downspouts run exactly as before. The birds have moved on.