Date: 1/14/25 12:42 pm From: PAUL ROBERTS <phawk254...> Subject: [MASSBIRD] Population Status of Rough-legged Hawk in Massachusetts
The recent sighting of a juvenile dark morph Rough-legged Hawk at Plum Island raised several questions as to the number of Roughlegs being seen in recent years. I find it cumbersome to respond to anything at any length on GrouptMe or any text mode, but for those interested there are two good sources of data on the population status of Rough-legged Hawk. The Raptor Population Index (rpi-project.org) analyzes multiple sources of data, not just migration counts, for most species. The Roughlrg is unusual in being one of the few North American raptors that totally evacuates its breeding grounds to migrates south. Over the past ten years 57% of the sites had "statistically significant stable counts." There were decreasing counts at 43% of the sites, and no sites reported increases. The 20-year trend is similar, with most decreases in eastern and central North America. Neil Paprocki and the Roughleg Hawk project report drastic changes in the winter distribution of Roughlegs in western North America. The southern limits of migration have shifted about 200 miles north over the last 30-40 years. Thus, winter populations in the west are significantly decreasing, but there is no hard evidence that there is an overall population decline. It's just that when Roughlegs migrate now they generally move south 200 miles less than during the 1970s and 80s, presumably because of climate change. For obvious reasons, most banded and radio-tagged Roughlegs are captured during migration, not on the breeding grounds. The Roughleg project began tagging and tracking Roughlegs in the west and has gradually been moving east. Everything suggests a more significant decline in Roughlegs in the east, but they are only beginning to tag and track eastern Roughlegs They don't know if there is a more significant reduction in the distance south they move or not, or if there is a significant decrease in the breeding population. Whatever, in general it seems (and my experience supports) that we are seeing far fewer Roughlegs in New England in the past 5–10 years than earlier. The Northeast Hawk Watch Hawk Migration Report annually reports migration count trends since 1980. Their migration counts cover only a portion of the Roughleg migration season, but within that limitation they show a rough "eyeball decline" of 60-80% over the past forty years. In other words, treasure every Roughleg you see, and please DO NOT chase or harass the birds. In my experience, in recent years locally Roughlegs have seemed to avoid hunting/roosting near people. Some of this might be due to changes in the distribution of microtines in their immediate area, but I tend to think some of it is intentionally avoiding large bipeds carrying apparent weapons (spotting scopes or large cameras, esp, on tripods.) It is also possible they realize that large bipeds toting apparent weapons prompt short furry mammals to cower in their burrows or tunnels, so food may be much harder to find when bipeds run amok. Whatever, I find most of my photos of Roughlegs in the past 5-10 years at Plum are a quarter to a half mile away, contrary to previous experience locally. I had no such problems photographing Roughlegs in the past ten years in Utah and Idaho. Best, Paul Paul M. Roberts Medford, MA <phawk254...>
