Osvel Hinojosa-Huerta

Cornell University | CU · Laboratory of Ornithology

Populations of secretive marsh birds (Rallidae and Ardeidae) have declined in North America in the last decades. Despite drastic habitat changes, the Colorado River delta supports four species of protected marsh birds: California Black Rail, Virginia Rail, Least Bittern and Yuma Clapper Rail. Our goal was to assess the status (2010–2011) and detect...

Many riparian zones in the Sonoran Desert have been altered by elimination of the normal flood regime; such changes to the flow regime have contributed to the spread of saltcedar (Tamarix ramosissma Ledeb.), an exotic, salt-tolerant shrub. It has been proposed that reestablishment of a natural flow regime on these rivers might permit passive restor...

We assessed the response of breeding birds to one decade of riparian restoration in the Colorado River delta including active vegetation management since 2010 and various environmental water deliveries since 2014. Bird surveys were conducted from 2002 to 2021 at 230 bird count stations distributed along five river reaches with different hydrogeomor...

We examined the influence of local habitat factors such as plant community composition and species cover, and landscape habitat factors (e.g., land cover types) on the composition of the avian community in an arid-region large river delta (Colorado River). This 106 river km-long study area has experienced restoration through environmental water del...

Ecological restoration is an essential strategy for mitigating the current biodiversity crisis, yet restoration actions are costly. We used systematic conservation planning principles to design an approach that prioritizes restoration sites for birds and tested it in a riparian forest restoration program in the Colorado River Delta. Restoration goa...

Historically, the Colorado River Delta was a biologically rich floodplain built on sediments over millions of years as the river slowed before draining into the Gulf of California. Today, after more than a century of dams, diversions, and development, the 3,000-square-mile ecosystem is effectively missing. Thousands of acres of irrigated farmland s...

The economic valuation of coastal ecosystem services is a critical step for the design of sound public policies that support the preservation of the services that nature provides to society in the context of climate change. Using the value transfer method, we obtained the economic valuation that represents the loss of coastal ecosystem services cau...

Restoration efforts have begun on a global scale, with the goal of reversing the impacts caused by exotic vegetation invading disturbed sites. The purpose of this study was to determine the response of amphibians and reptiles to habitat restoration in the Colorado River Delta, by comparing the richness and diversity of the herpetofauna in 2 restore...

1. Above 288N, the coastline of the northern Gulf of California is indented at frequent intervals by negative or inverse estuaries that are saltier at their backs than at their mouths due to the lack of freshwater inflow. These 'esteros' total over 215 000 ha in area and encompass mangrove marshes below 298N and saltgrass (Distichlis palmeri) marsh...

In this study we focused on urban bird diversity across Mexico, a megadiverse country, with a special focus on the relative role of urban greenspaces and heavily-built sites. We considered a country-wide approach, including 24 different sized Mexican cities. Our aims were to describe the urban bird diversity in focal cities and further assess the r...

Since the late 1970s, periodic river releases, agricultural return flows, and treated effluent of wastewater plants have revitalized portions of the delta, and the populations of some waterbird species have responded accordingly (Glenn et al. 2001; HinojosaHuerta et al. 2004). This resiliency in the delta has been attributed to a number of key elem...

Environmental flows have become important tools for restoring rivers and associated riparian ecosystems (Arthington, 2012; Glenn et al., 2017). In March 2014, the United States and Mexico initiated a bold effort in restoration, delivering from Morelos Dam a “pulse flow” of water into the Colorado River in its delta for the purpose of learning about...

Minute 319, a binational agreement between the United States and México, authorized environmental flows into the Colorado River Delta, including a high-profile pulse flow delivered in March through May 2014. Reforming water management policy to secure future delivery of environmental flows to the delta hinges on demonstrating the feasibility of del...

A large pulse of water is planned to be released into the dry Colorado River channel in Mexico. This engineered experimental spring flood, which will flow from Lake Mead and pass through downstream reservoirs, is the culmination of decades of applied research. The pulse flow is a rare opportunity for research at the landscape scale [Glenn et al., 2...

Wetland areas have been drastically reduced through the Pacific Flyway and the Sonoran Desert, with severe consequences for avian populations. In the Colorado River delta, wetlands have been reduced by 80 percent due to water management practices in the Colorado River basin. However, excess flows and agricultural drainage water has restored some ar...

The Ciénega of Santa Clara is a valuable coastal wetland sustained almost entirely by discharge of brackish agricultural drain water from the U.S. and Mexico. In other locations, agricultural drain water has been problematic in supporting wetlands due to problems of salinity buildup, toxic substances and undesirable plant succession processes. We s...

In arid lands, wetland loss is the result not only of the scarcity of water itself, but also of the management of water to maximize off-stream uses. In the Colorado River delta, Mexico, no in-stream flows are allocated for aqutic ecosystems, yet agricultural return flows and canal operational releases support 36,377 ha of valuable wetland and ripar...

The 1977 creation of the Cienega de Santa Clara, an 18,000 ha wetland (6500 ha cattail marsh with 11,500 ha of open water lagoons and mudflats) in Sonora, Mexico, was the unintended consequence of the solution to reduce the salinity of the U.S. water deliveries to Mexico. Under the 1944 Water Treaty, the U.S. was obliged to deliver water to Mexico....

El río Colorado es la fuente de vida para el suroeste de Estados Unidos y el noroeste de México. La cuenca transfronteriza del Colorado abarca un área de más de 630,000 km2 en la que habitan más de 30 millones de personas en ambos países. Desde su nacimiento en las Montañas Rocallosas en Estados Unidos, el río recorre más de 2,300 km en dirección s...

Este trabajo representa una revisión y actualización de la avifauna del estado de Sonora, México. La revisión incluyó registros de 89 artículos y reportes, 16 008 especímenes depositados en colecciones zoológicas de diferentes museos y más de doscientos setenta y ocho mil registros que corresponden a observaciones de campo y datos de anillamiento g...

The Colorado River basin in the U.S. and Mexico is vital to both the ecology and economy of western North America. The river provides water to over 30 million people and to irrigate between 1.2 and 1.6 million hectares of agricultural land. A vast effort has been conducted to control, store and divert the river flows, and now the total storage capa...

The delta of the Colorado River in Mexico supports a rich mix of estuarine, wetland and riparian ecosystems that provide habitat for over 350 species of birds as well as fish, marine mammals, and other wildlife. An important part of the delta ecosystem is the riparian corridor, which is supported by agricultural return flows and waste spills of wat...

Like other great desert rivers, the Colorado River in the United States and Mexico is highly regulated to provide water for human use. No water is officially allotted to support the natural ecosystems in the delta of the river in Mexico. However, precipitation is inherently variable in this watershed, and from 1981-2004, 15% of the mean annual flow...

We studied the reproductive ecology and behavior of the black murex snail, Hexaplex nigritus (Philippi, 1845), a species heavily harvested in the Gulf of California, Mexico. We found that H. nigritus is dioacious and highly gregarious, capable of forming breeding aggregations with a biomass of 3 mt. Snails aggregated in subtidal waters between Apri...

We determined the spatial and temporal patterns of avian species richness and density and explored their relationships with habitat features in the floodplain of the Colorado River in Mexico, which was subject to regeneration through pulse-floods in the last 20 yr. Our work included monthly point counts at 30 transects (240 points) from May 2002-Ju...

The Yuma Clapper Rail (Rallus longirostris yumanensis) is a binationally protected marsh bird in northwestern Mexico and southwestern US. We monitored the population of Yuma Clapper Rails in the Colorado River delta, Mexico from 1999–2006. The monitoring program consists of callresponse surveys at 15 transects (fi ve point counts each) randomly loc...

Arid zone rivers have highly variable flow rates, and flood control projects are needed to protect adjacent property from flood damage. On the other hand, riparian corridors provide important wildlife habitat, especially for birds, and riparian vegetation is adapted to the natural variability in flows on these rivers. While environmental and flood...

A little more than thirty years ago, the Colorado River Delta (the “Delta”) was considered all but a dead ecosystem by scientists and environmental organizations alike. Once one of the largest wetland ecosystems in North America, a century of dam building, upstream water diversions, and agricultural development in the Mexicali Valley had reduced mi...

In this chapter we describe some of the unique characteristics of the avifauna of the Alto Golfo. We also present the status of bird communities in the different areas of the Alto Golfo, including the Colorado River delta, the Pinacate Region and the Gran Desierto, complemented with an annotated checklist of birds. Finally, we discuss some of the m...

Organic contaminants (organochlorine [OC], organophosphorus [OP] pesticides and polychlorinated biphenyls [PCBs]), and metals (As, Cd, Hg, Pb, and Se) are a concern to avian health in the Colorado River delta, Mexico. We determined concentrations of contaminants in eggs of three breeding species of birds from the delta (mourning doves [Zenaida macr...

I evaluated the spatial and temporal patterns of the avian communities in the Colorado River delta, Mexico, and their relationship with vegetation type and surface water. I also developed plausible conservation and restoration guidelines for riparian areas and native birds in the region. The study included monthly point counts at 30 transects (240...

1.Above 28°N, the coastline of the northern Gulf of California is indented at frequent intervals by negative or inverse estuaries that are saltier at their backs than at their mouths due to the lack of freshwater inflow. These ‘esteros’ total over 215 000 ha in area and encompass mangrove marshes below 29°N and saltgrass (Distichlis palmeri) marshe...

This report provides a comprehensive description of the results from the “Mapping Conservation Priorities in the Colorado River Delta: A State-of-Knowledge Workshop,” held in October 2002. The workshop was designed to produce results that will help guide conservation programs and projects for the next two decades in the Colorado River Delta and Upp...

Wetland areas have been drastically reduced through the Pacific Flyway and the Sonoran Desert, with severe consequences for avian populations. In the Colorado River delta, wetlands have been reduced by 80 percent due to water management practices in the Colorado River basin. However, excess flows and agricultural drainage water has restored some ar...

Despite extensive losses of wetlands caused by water diversions upstream, the Colorado River Delta in northwestern México remains an important wetland system in the Sonoran Desert. The purpose of our study was to describe waterbird communities across a variety of wetland habitat types and zones that exist in the Delta. We measured species richness...

This Bird Conservation Plan (BCP) is a joint effort among agencies, government, and stakeholders that have been working towards the conservation of the Colorado River delta. The general guidelines of the BCP include protecting all bird species, helping species at risk, maintaining common birds common, and basing all actions on collaborative, volunt...

Seepage from the All-American Canal has created a series of wetlands totaling over 6200 hectares (15,500 acres) along the U.S.-Mexico border. Over half of these are in Mexico, east of the portion of the canal that is proposed for lining, and will therefore be impacted by lack of further seepage. The Andrade Mesa Wetlands are extensive and provide h...

During March–June 2000 we evaluated the use of call-response surveys to monitor breeding Yuma Clapper Rails (Rallus longirostris yumanensis) at the Cie´nega de Santa Clara, Colorado River Delta, Sonora, Mexico. We assessed the effect that time of day, stage of breeding season, and number of survey periods had on the average number of rails detected...

We estimated the abundance of Yuma clapper rails in the Ciénega de Santa Clara and determined the distribution of the subspecies in the Colorado River delta region in México. The maximum estimate of abundance was 6629 individuals (95% C.I. 4859–8399), assuming a response rate by rails to taped calls of 60%. Rails were widely distributed in the delt...

A subspecies of willow flycatcher, the south-western willow flycatcher, has become endangered in the U.S. The objective of this study was to determine the presence/absence of this subspecies in the Colorado River delta. Surveys were conducted in June–July 1999 and in May–June 2000. We detected a total of 50 birds, most likely south-western willow f...

Populations of California Black Rails (Laterallus jarnaicensis coturniculus) have been drastically reduced in western North America over the last several decades (Repking and Ohmart 1977, Evens et al. 1991). The California Black Rail is listed as threatened by the California Department of Fish and Game and is considered a "species of concern" by th...

I conducted call-response surveys for Yuma clapper rails in the Colorado River delta, Mexico during the breeding seasons of 1999 and 2000 to estimate abundance, determine distribution, and identify patterns of habitat use. The maximum estimate of abundance was 6,629 individuals (95% C.I. 4,859 to 8,399). Rails were widely distributed in the delta,...

Este documento es resultado de un proyecto binacional y multi institucional que busca restaurar los humedales del delta del Río Colorado. Dentro de las actividades que se han realizado en el proyecto se encuentran la integración de un Sistema de Información Geográfica, el análisis de vegetación y valor de hábitat, el análisis de calidad de agua y e...

The Information Database and Local Outreach Program for the Restoration of the Hardy River Wetlands in the Lower Colorado River Delta, Baja California and Sonora, Mexico was accomplished under the generous funding of the North America Wetlands Conservation Council, ITESM Campus Guaymas, University of Arizona, Pronatura Sonora, Environmental Defense...

Resumen La cuenca del río Colorado en Estados Unidos y México es vital para la ecología y la economía del oeste de Norteamérica. El río provee agua para más de 30 millones de personas y para la irrigación de entre 1.2 y 1.6 millones de hectáreas de terrenos agrícolas. Se han realizado grandes esfuerzos en la cuenca para controlar, almacenar y deriv...