library(dplyr)

nests<-df %>%
    filter(type %in% "Nest2017")

library(maptools)
library(sp)
library(rgeos)

nests$lon <- as.numeric(as.character(nests$lon))
nests$lat <- as.numeric(as.character(nests$lat))
coordinates(nests) <- c("lon", "lat")

proj4string(nests) <- CRS("+init=epsg:3578") #setting the projection of the points

spTransform(nests,CRS("+init=epsg:3578")) #tranforming the coordinates

gBuffer(nests, width=30, byid=TRUE) #puts a circular buffer around each individual point

lat                  lon                NatalMidden   squirrelID    type
60.9577819984406    -138.0347849708050  -27           NA            Nest2017
60.9574120212346    -138.0345689691600  -27           NA            NatalMidden
60.9578209742904    -138.0346520338210  -27           23054         Foray
60.9575380012393    -138.0348329991100  -27           23054         Foray
60.9576250053942    -138.0339069664480  -27           23054         Foray
60.957643026486     -138.0338829942050  -27           23054         Foray
60.9575670026243    -138.0348739866170  -27           23054         Foray
60.9600000176579    -138.032592013478   -515          22780         Foray
60.9600180387497    -138.032631995156   -515          22780         Foray
60.9599519893527    -138.032342987135   -515          NA            NatalMidden
60.959974033758     -138.032317003235   -515          NA            Nest2017

> df = read.table("./figshare.txt",sep="t",head=TRUE)
> df = st_as_sf(df, coords=c("lon","lat"))
> st_crs(df)=4326
> df = st_transform(df, 3578)
> plot(df$geometry,col=df$type,pch=19)

> Forays = df[df$type=="Foray",]
> Nests = df[df$type=="Nest2017","NatalMidden"]

> Forays = dplyr::left_join(Forays, data.frame(Nests), c("NatalMidden"="NatalMidden"))
> head(Forays)
Simple feature collection with 6 features and 3 fields
Active geometry column: geometry.x
geometry type:  POINT
dimension:      XY
bbox:           xmin: 200427.2 ymin: 731035 xmax: 200451.7 ymax: 731043.8
epsg (SRID):    3578
proj4string:    +proj=aea +lat_1=61.66666666666666 +lat_2=68 +lat_0=59 +lon_0=-132.5 +x_0=500000 +y_0=500000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs
  NatalMidden sq_id  type                geometry.x                geometry.y
1        -515 22780 Foray   POINT (200427.3 731035) POINT (200465.3 731052.2)
2        -515 22780 Foray POINT (200446.1 731041.4) POINT (200465.3 731052.2)
3        -515 22780 Foray POINT (200450.9 731043.5) POINT (200465.3 731052.2)
4        -515 22780 Foray POINT (200451.7 731043.8) POINT (200465.3 731052.2)
5        -515 22780 Foray POINT (200448.5 731042.7) POINT (200465.3 731052.2)
6        -515 22780 Foray   POINT (200427.2 731035) POINT (200465.3 731052.2)
                  geometry
1 GEOMETRYCOLLECTION EMPTY
2 GEOMETRYCOLLECTION EMPTY
3 GEOMETRYCOLLECTION EMPTY
4 GEOMETRYCOLLECTION EMPTY
5 GEOMETRYCOLLECTION EMPTY
6 GEOMETRYCOLLECTION EMPTY

> Forays$geometry = NULL
> Forays$dist = st_distance(Forays$geometry.x, Forays$geometry.y, by_element=TRUE)
> head(Forays)
Simple feature collection with 6 features and 4 fields
Active geometry column: geometry.x
geometry type:  POINT
dimension:      XY
bbox:           xmin: 200427.2 ymin: 731035 xmax: 200451.7 ymax: 731043.8
epsg (SRID):    3578
proj4string:    +proj=aea +lat_1=61.66666666666666 +lat_2=68 +lat_0=59 +lon_0=-132.5 +x_0=500000 +y_0=500000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs
  NatalMidden sq_id  type                geometry.x                geometry.y
1        -515 22780 Foray   POINT (200427.3 731035) POINT (200465.3 731052.2)
2        -515 22780 Foray POINT (200446.1 731041.4) POINT (200465.3 731052.2)
3        -515 22780 Foray POINT (200450.9 731043.5) POINT (200465.3 731052.2)
4        -515 22780 Foray POINT (200451.7 731043.8) POINT (200465.3 731052.2)
5        -515 22780 Foray POINT (200448.5 731042.7) POINT (200465.3 731052.2)
6        -515 22780 Foray   POINT (200427.2 731035) POINT (200465.3 731052.2)
          dist
1 41.69695 [m]
2 21.97295 [m]
3 16.79233 [m]
4 15.91557 [m]
5 19.27717 [m]
6 41.79212 [m]