The Hudson Valley Lyme Record Does Not Show Nymph Surges Are 'Not Deer'

The Factum's strongest overclaim is the HELIX line that a 35-year Hudson Valley record links blacklegged-tick nymph surges to white-footed mice and acorn mast, 'not deer.' That 'not' is the error. Richard Ostfeld's own synthesis does not erase deer. The 2006 PLoS Biology paper is titled 'Climate, Deer, Rodents, and Acorns as Determinants of Variation in Lyme-Disease Risk' (Ostfeld, Canham, Oggenfuss, Winchcombe, Keesing). Deer are in the model, not outside it. What the mast-mouse chain actually explains is year-to-year swings in nymphal risk inside forests where white-tailed deer are already common enough to complete the tick's life cycle. Correlation under saturation is not evidence of irrelevance. The life cycle makes a blanket 'not deer' claim biologically false. Larvae and nymphs feed on mice and other small hosts, which is why mice drive Borrelia prevalence and why an acorn boom predicts a nymph boom two summers later. Adult females, though, take their final blood meal mainly on deer, mate, and lay the eggs that produce the next larval cohort. CDC's vector guidance states the same split: deer are essential reproductive hosts even though they are not the Lyme reservoir. Experiments that change deer, rather than just count mice, move nymph numbers. After deer were eliminated from Monhegan Island, Maine, Ixodes scapularis collapsed: adult ticks crashed and subsequent nymphal stages fell with them (Rand, Lubelczyk, Holman, Lacombe, Smith, Journal of Medical Entomology, 2004). In Connecticut, sharp reductions in local deer density were followed by lower abundance of I. scapularis (Stafford, Denicola, Kilpatrick, Journal of Medical Entomology, 2003). Earlier mainland work found tick abundance tracking deer (Wilson, Adler, Spielman, Annals of the Entomological Society of America, 1985). Those results are messy at moderate deer densities, and mouse-targeted interventions still matter for infection rate. They do not license the headline negation. The Factum pattern this cycle is corrective narrowing that overshoots: priority boarding is not a bin reservation, Social Security is not an SEC Ponzi, valley fog is not a climate signal. Those distinctions hold. 'Not deer' does not. Mice and acorns time the surge; deer make the surge possible.