An aerial photo taken in the growing season records the vegetation tops on its flight date. Deer choose bedding cover down at ground level, which a summer image cannot measure. This guide uses five classes to sort dark patches by what the picture supports and what needs an image from a later date or a walk to resolve. That way, the bedding zones you mark are based on cover you have checked and confirmed.
STEP 1 · What the photo is
Summer foliage seen overhead records a single day's conditions
The National Agriculture Imagery Program (NAIP) provides a useful reference for leaf-on imagery, with detailed documentation from USGS. These aerial photos are corrected for terrain and camera angle and cover the contiguous United States during agricultural growing seasons, with leaves on the vegetation. Ground resolution measured 1 meter from 2003 to 2017; the standard changed to 0.6 meter in 2018. Flights shifted from a five-year cycle (2003 to 2009) to a cycle of no more than three years. A tile can have up to 10 percent cloud cover. The contracts set an accuracy requirement: well-defined points must be within 6 meters of their true positions on the ground at 95 percent confidence, roughly 20 feet. Allow more uncertainty along the edge of a feature without a sharp boundary, such as a thicket.
That leaves two limits when judging cover. A pixel records the uppermost surface present when the aircraft passed. The interval between photographs of the same location can span years. Our leaf-off imagery guide explains how to check the vintage of imagery in your app. Here, we leave that check there and examine what a dated picture can tell you about cover.
STEP 2 · Canopy and cover
An unbroken canopy shows where the woods are but tells you nothing about the layer at ground level
The wildlife land assessment guide names four basic needs shared by all species: food, water, shelter and space. It also explains that deer, songbirds and wild turkeys may visit a property to meet just some of those needs. Apply the same reasoning when looking at a photo. A dark patch of timber confirms the presence of woods, but the image does not reveal the thickness of the understory.
In Purdue's management table, land use affects the vegetation beneath the treetops. Excluding livestock from woodland appears as a method for producing "thicker stem density for cover." Allowing woodland borders to develop shrubs, blackberry growth and vines appears as a food-and-cover source. Woodland with grazing and woodland without it can show identical treetop cover in an overhead view.
Illinois wildlife guidance calls the state's deer generalists. They live within or near woodland, especially beside streams or adjoining agricultural land. The guidance says deer feed beyond the trees but depend on woodland to survive. Timber therefore contributes to the answer. Summer imagery locates it effectively, yet cannot judge its quality.
We define bedding by a zone of cover, never by a pinpoint tied to terrain. The Reading the Ground paper explains that distinction through landforms: terrain indicates travel locations, while cover indicates bedding locations. For an approach centered on cover in level country, read Finding Buck Bedding in Flat Farmland.
Claims imagery with leaves present can back
- Telling fields from woods over an area the size of a farm.
- Gaps within woodland, including timber-loading areas and recently built pads.
- Exposed water present when the aircraft passed.
- Boundaries with human development, including homes, access lanes, outbuildings and lots.
Claims that imagery cannot back
- The concentration of stems beneath treetops.
- The plants composing a brush patch, or a dependable answer about whether mowing preceded the flight over a grassy field.
- Bedding for the current year. Beds lie near the ground, concealed beneath the upper canopy.
- The presence of deer. Green shading establishes vegetation, without establishing either usable cover near the ground or use by deer.
STEP 3 · Five classes
Assign each dark area a class before adding it to your hunting map
Require a single classification for each patch. An area that fits none has yet to qualify as a hunting candidate. This table comes from our working process; it is no published census of cover.
Swipe table to see every column
| Class | What the leaf-on photo can support | What only a walk or a later image settles | Treat it on the map as |
|---|---|---|---|
| A. Closed canopy, understory unknown | Timber versus field; openings | Stem density, blowdown, grazing, trails | Woods, capability only |
| B. Evergreen or dense young growth | A dark patch in summer; if it stays dark on a winter image, possibly evergreen | Cedar, pine plantation or shrub; how thick it is at eye level | Cover candidate |
| C. Open grass or crop | Field pattern, rows, pivots | This year's crop, harvest state, how tall a grass field stands | Food candidate |
| D. Wet basin | Open water or wet soil on the flight date | Whether it holds water now | Water candidate |
| E. Human edge | Roofs, lanes, lots | Who is there and when | Pressure flag |
Purdue includes small plantings of conifers in its table as shelter in severe weather. That supports calling class B a candidate. The image still cannot establish whether the particular patch offers usable shelter under those conditions.
Keep classifications grounded with three rules
- Choose one main class for each patch. Putting cover, food and water claims on the same marker makes it hard to tell which claim you have examined. Any patch can also carry a class E flag.
- Move a patch into a higher class only with support from a subsequent photograph or an on-foot check.
- Summer foliage imagery never establishes bedding in a patch. Candidate cover is its strongest supported designation. Any bedding marked afterward must occupy a shaded zone across confirmed cover, never a pinpoint based on color.
Picture a dark patch of woods between a bean field and a home. That image supports class A with an E flag: timber near people. Plan a late-summer walk along the downwind edge, on land you own or have permission to enter. Leave an October sit in the center out of the plan. Bring a winter photo into the decision, too. The leaf-off guide explains how winter images distinguish timber types by color and texture: oak ridges look bare and gray, cedar draws look dark, and brushy cuts have a feathery texture. A stand that looks like bare gray hardwoods and shows no dark or brushy patches gets the last spot on the walking list. A patch still dark in January shifts into class B and gets the first spot.
STEP 4 · Field check
Check the downwind boundary; three questions decide whether the patch stays
Keep the walk along the boundary, never through the center. Restrict access to your own land or land where entry is permitted. An on-foot check can resolve three questions the image cannot:
Withdraw the cover designation that day if chest-level visibility extends through the area for 20 yards. A single visit samples a single day. Finding sign establishes use sometime in the past; it establishes neither timing nor frequency.
STEP 5 · Second date
A newer photo resolves questions about objects, but never about animals
A winter photo records the ground on a different flight date; it does not show conditions today. When pictures from two dates disagree, use the newer one for visible objects, but trust neither picture for animals. The leaf-off guide explains what winter imagery reveals about woodland edges, thickets and trails. Here, the scope ends with classification.
STEP 6 · Next step
Choose a class, record a reason to reject the patch, and check it on foot
Choose a single dark area within your hunting county and assign its class. Record one observation that would disqualify it, perhaps an unobstructed view extending 20 yards. Visit the spot afterward to examine what remains hidden in the image.
To pair this check with winter imagery, explore the mapping coverage. Our map features page describes Illinois coverage statewide with 6-inch imagery captured without leaves in 2025. Timber in Pike County supplies the illustration.
What a Leaf-On Aerial Can and Cannot Tell You About Cover
Checklist
NOTES AND SOURCES
- Aerial photos, terrain data and parcel layers show the land as it was when the information was captured or recorded. Those layers are neither land surveys nor legal boundary lines.
- This material promises neither deer activity nor a successful hunt. Before hunting, check the applicable seasons and rules and confirm your permission.
Fully Drawn Research is an independent data analysis desk, not affiliated with any state wildlife agency, transportation agency, mapping provider or outfitter. FDR maps give context from public imagery, terrain, and parcel records; they do not predict deer activity or replace a field check.
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