Deep object detection for waterbird monitoring
using aerial imagery
Krish Kabra∗,†,‡, Alexander Xiong†,‡, Wenbin Li†,‡, Minxuan Luo‡, William Lu‡,
Tianjiao Yu‡, Jiahui Yu‡, Dhananjay Singh‡, Raul Garcia‡, Maojie Tang‡,
Hank Arnold§, Anna Vallery§, Richard Gibbons¶, Arko Barman§
‡Rice University, Houston, TX 77005, USA
§Houston Audubon Society, Houston, TX 77079, USA
¶American Bird Conservancy, The Plains, VA 20198, USA
Abstract—Monitoring of colonial waterbird nesting islands is
essential to tracking waterbird population trends, which are
used for evaluating ecosystem health and informing conservation
management decisions. Recently, unmanned aerial vehicles, or
drones, have emerged as a viable technology to precisely monitor
waterbird colonies. However, manually counting waterbirds from
hundreds, or potentially thousands, of aerial images is both
difficult and time-consuming. In this work, we present a deep
learning pipeline that can be used to precisely detect, count,
and monitor waterbirds using aerial imagery collected by a
commercial drone. By utilizing convolutional neural network-
based object detectors, we show that we can detect 16 classes of
waterbird species that are commonly found in colonial nesting
islands along the Texas coast. Our experiments using Faster
R-CNN and RetinaNet object detectors give mean interpolated
average precision scores of 67.9% and 63.1% respectively.
Index Terms—Object detection, Convolutional neural net-
works, Wildlife monitoring
I. INTRODUCTION
Colonial waterbird nesting islands can be found across
the globe, and each of North America’s coasts is home to
its own species of breeding colonial waterbirds. Colonial
waterbirds are important indicators of ecosystem health [1],
provide numerous ecosystem services, and are an important
part of a growing nature-based tourism sector of the economy
[2]. Therefore, continuing research and monitoring of these
species is critical to inform conservation decisions, encourage
management of habitats for the benefit of colonial waterbirds,
and to continue to gauge the surrounding ecosystem health.
Monitoring of waterbirds at colonial nesting islands is a
widespread technique used to track population trends. There
are many colonial waterbird monitoring programs in the U.S.
including the Texas Colonial Waterbird Survey, which is one of
the longest running programs that monitors waterbirds across
the entire Texas coast annually since 1976 [3]. Censusing
waterbirds on islands is no small task. Traditional monitoring
studies of waterbirds have been conducted by traversing the
colony on foot, surveying via boat, or surveying aerially using
small, manned aircraft. Each of these methods has its own
set of challenges and consequences. Surveying waterbirds by
foot can disturb both the species of interest and the habitat
†Denotes equal contribution. ∗Corresponding author: kk80@rice.edu
occupied. Low vantage points of boat-based surveys can result
in the risk of missing nests, particularly on larger and higher
islands. Moreover, in certain conditions, accessing the islands
by boat can be tricky due to inclement weather conditions.
Manned aerial surveys is the preferred technique by state and
federal wildlife agencies, but these are expensive and require
the proper conditions. In fact, aircraft crashes and boating
accidents have been found to be the largest causes of mortality
and injury among biologists in the field [4].
In recent years, unmanned aerial vehicles (UAVs), also
referred to as drones, have presented themselves as a useful
tool in wildlife management [5], [6], including waterbird
monitoring [7], [8]. Drones allow researchers to remain safely
on the ground while surveying areas of interest with both
less cost and greater ease than traditional aerial surveys. In
studies where this technology has been applied, the use of
drones was found to result in more precise count estimates
than traditional ground-based surveys [9]. Unfortunately, the
expertise and time required to manually localize and classify
species from hundreds, potentially thousands, of aerial images
represents a major bottleneck.
To alleviate this issue, we developed a object detection-
based deep learning pipeline that utilizes convolutional neural
networks (CNNs) [10]–[12] to precisely localize and classify
colonial waterbird species from UAV aerial imagery via super-
vised learning. We collect survey images from three colonial
nesting islands along the Texas coast, and train a CNN-based
object detection model to detect 16 classes of waterbirds, in-
cluding the 14 most common colonial waterbird species found
on these islands: Brown Pelican (Pelecanus occidentalis),
Laughing Gull (Leucophaeus atricilla), Royal Tern (Thalasseus
maximus), Sandwich Tern (Thalasseus sandvicensis), Great
Egret (Ardea alba), Cattle Egret (Bubulcus ibis), Snowy Egret
(Egretta thula), Reddish Egret (Egretta rufescens), American
White Ibis (Eudocimus albus), Great Blue Heron (Ardea
Herodias), Black-crowned Night Heron (Nycticorax nyctico-
rax), Tri-colored Heron (Egretta tricolor), Roseate Spoonbill
(Platalea ajaja), and Black Skimmer (Rynchops niger). We
present results using two of the most commonly implemented
CNN-based object detection models, Faster R-CNN [11] and
RetinaNet [12].
arXiv:2210.04868v2 [cs.CV] 13 Oct 2022