library(RTMB)

tick <- read.table("Elston2001_tickdata.txt", header=TRUE, colClasses=c("factor","numeric","factor","numeric","factor","factor"))
tick$cHEIGHT <- tick$HEIGHT-mean(tick$HEIGHT)

par <- list(alpha=0, beta=numeric(nlevels(tick$YEAR)), logSdI=0, logSdB=0, logSdL=0,
            zI=numeric(nlevels(tick$INDEX)), zB=numeric(nlevels(tick$BROOD)), zL=numeric(nlevels(tick$LOCATION)))

f <- function(par){  
  getAll(par,tick)
  jnll <- 0  
  jnll <- jnll - sum(dnorm(zI, 0, sd=exp(logSdI),log=TRUE))
  jnll <- jnll - sum(dnorm(zB, 0, sd=exp(logSdB),log=TRUE))
  jnll <- jnll - sum(dnorm(zL, 0, sd=exp(logSdL),log=TRUE))
  logLambda <- alpha*cHEIGHT+beta[YEAR]+zI[INDEX]+zB[BROOD]+zL[LOCATION]
  jnll <- jnll - sum(dpois(TICKS, exp(logLambda), log=TRUE))
  jnll
}

obj <- MakeADFun(f, par, random=c("zI","zB","zL"), silent=TRUE)
fit <- nlminb(obj$par, obj$fn, obj$gr)

# same as: 
# glmmTMB::glmmTMB(TICKS ~ -1+as.factor(YEAR)+cHEIGHT+(1|LOCATION)+(1|BROOD)+(1|INDEX), family=poisson, data=tick)